Atoms, Ions, and the Periodic TableAtoms, Ions, and the Periodic Table

What is an atom?What is an atom?

It is smallest particle of an element that It is smallest particle of an element that retains the elements properties.retains the elements properties.

But how did we come to know all the But how did we come to know all the information we have about these tiny information we have about these tiny particle?particle?

DemocritusDemocritus (460-370 BC) (460-370 BC)

DemocritusDemocritus (460-370 BC) (460-370 BC) MatterMatter is made of is made of tiny, solid, indivisible particlestiny, solid, indivisible particles which he which he

called atoms (from called atoms (from atomosatomos, the Greek word for , the Greek word for indivisible).indivisible).

Different Different kinds of kinds of atomsatoms have have different sizes and shapesdifferent sizes and shapes.. Different Different properties of matterproperties of matter are due to the differences are due to the differences

in in size, shape, and movement of atomssize, shape, and movement of atoms. . Democritus’ ideas, though correct, were widely Democritus’ ideas, though correct, were widely rejectedrejected

by his peers, most notably by his peers, most notably AristotleAristotle (384-322 BC). (384-322 BC). Aristotle was a very influential Greek philosopher who Aristotle was a very influential Greek philosopher who had a different view of matter. He believed that had a different view of matter. He believed that everything was composed of the four elements earth, air, everything was composed of the four elements earth, air, fire, and water. Because at that time in history, fire, and water. Because at that time in history, Democritus’ ideas about the atom could not be tested Democritus’ ideas about the atom could not be tested experimentally, the opinions of well-known Aristotle won experimentally, the opinions of well-known Aristotle won out. Democritus’ ideas were not revived until John out. Democritus’ ideas were not revived until John Dalton developed his atomic theory in the 19th century! Dalton developed his atomic theory in the 19th century!

John DaltonJohn Dalton (1766-1844) (1766-1844)

John DaltonJohn Dalton (1766-1844) (1766-1844)

All All mattermatter is is composedcomposed of extremely small of extremely small particles called particles called atomsatoms..

All All atoms of one elementatoms of one element are are identicalidentical.. AtomsAtoms of a given element are of a given element are differentdifferent from from

those of those of any other elementany other element. . Atoms of one element combine with atoms Atoms of one element combine with atoms

of another element to of another element to form compoundsform compounds.. Atoms are iAtoms are indivisiblendivisible. In addition, they . In addition, they

cannot be created or destroyedcannot be created or destroyed, just , just rearranged.rearranged.

Dalton’s theory was of critical importance. Dalton’s theory was of critical importance. He was able to support his ideas through He was able to support his ideas through experimentation, and his work revolutionized experimentation, and his work revolutionized scientists’ concept of matter and its smallest scientists’ concept of matter and its smallest building block, the atom.building block, the atom.

Dalton’s theory has two flawsDalton’s theory has two flaws:: In point #2, this is not completely true. Isotopes In point #2, this is not completely true. Isotopes

of a given element are of a given element are not totally identicalnot totally identical; they ; they differ in the number of neutrons. Scientists did differ in the number of neutrons. Scientists did not at this time know about isotopes.not at this time know about isotopes.

In point #5, In point #5, atoms are not indivisibleatoms are not indivisible. Atoms . Atoms are made of even smaller particles (protons, are made of even smaller particles (protons, neutrons, electrons). Atoms neutrons, electrons). Atoms cancan be broken be broken down, but only in a down, but only in a nuclearnuclear reaction, which reaction, which Dalton was unfamiliar with. Dalton was unfamiliar with.

Discovery of the Electron Discovery of the Electron JJ ThomsonJJ Thomson (1856-1940) (1856-1940)

Discovery of the Electron Discovery of the Electron JJ ThomsonJJ Thomson (1856-1940) (1856-1940)

Discovered the Discovered the electronelectron, and determined that it had a , and determined that it had a negative chargenegative charge, by experimentation with cathode ray , by experimentation with cathode ray tubes. A cathode ray tube is a glass tube in which tubes. A cathode ray tube is a glass tube in which electrons flow due to opposing charges at each end. electrons flow due to opposing charges at each end. Televisions and computer monitors contain cathode Televisions and computer monitors contain cathode ray tubes. ray tubes.

Thomson developed a model of the atom called the Thomson developed a model of the atom called the plum puddingplum pudding model model. It showed evenly distributed . It showed evenly distributed negative electrons in a uniform negative electrons in a uniform positive cage.positive cage.

Diagram of plum pudding model:Diagram of plum pudding model:

Discovery of the NucleusDiscovery of the NucleusErnest Rutherford (1871-1937)Ernest Rutherford (1871-1937)

http://www.mhhe.com/physsci/chemistry/animations/chang_2e/rutherfords_experiment.swf

Discovery of the NucleusDiscovery of the NucleusErnest Rutherford (1871-1937)Ernest Rutherford (1871-1937)

Discovered the Discovered the nucleusnucleus of the atom in his of the atom in his famous famous Gold Foil ExperimentGold Foil Experiment. .

Alpha particles (helium nuclei) produced from the Alpha particles (helium nuclei) produced from the radioactive decay of polonium streamed toward a radioactive decay of polonium streamed toward a sheet of gold foil. To Rutherford’s great surprise, sheet of gold foil. To Rutherford’s great surprise, some of the alpha particles bounced off of the some of the alpha particles bounced off of the gold foil. This meant that they were hitting a gold foil. This meant that they were hitting a dense, relatively large object, which Rutherford dense, relatively large object, which Rutherford called the called the nucleusnucleus. .

Rutherford then discovered the Rutherford then discovered the protonproton, and next, working with a , and next, working with a colleague, James Chadwick (1891-1974), he discovered the colleague, James Chadwick (1891-1974), he discovered the neutronneutron as well.as well.

Questions about Rutherford’s experiment:Questions about Rutherford’s experiment:I. I. If gold atoms were solid spheres stacked together with no space between If gold atoms were solid spheres stacked together with no space between

them, what would you expect would happen to particles shot at them. them, what would you expect would happen to particles shot at them. Explain your reasoning.Explain your reasoning.The He nucleus would have been deflected straight back because it would The He nucleus would have been deflected straight back because it would have a much larger, heavier particle.have a much larger, heavier particle.

2.2. What does Ernest Rutherford’s experiment suggest about the structure of What does Ernest Rutherford’s experiment suggest about the structure of the atom; in other words, how can Rutherford’s evidence be used to correct the atom; in other words, how can Rutherford’s evidence be used to correct the plum pudding model? Draw a diagram.the plum pudding model? Draw a diagram.

   It shows there must be a dense area of great mass in the atomIt shows there must be a dense area of great mass in the atom  3. 3. Can you explain why Rutherford concluded that the mass of the gold Can you explain why Rutherford concluded that the mass of the gold

nucleus must be much greater than the mass of an alpha particle (helium nucleus must be much greater than the mass of an alpha particle (helium nucleus)?nucleus)?

     The He nucleus was deflected or reflected and couldn’t move the nucleusThe He nucleus was deflected or reflected and couldn’t move the nucleus4.4. Do you think that, in Rutherford's experiment, the Do you think that, in Rutherford's experiment, the electronselectrons in the gold in the gold

atoms would deflect the alpha particles significantly? Why or why not?atoms would deflect the alpha particles significantly? Why or why not?No, because the He nucleus has a much greater mass than an electron.No, because the He nucleus has a much greater mass than an electron.

5.5. Rutherford experimented with many kinds of metal foil as the target. The Rutherford experimented with many kinds of metal foil as the target. The results were always similar. Why was it important to do this?results were always similar. Why was it important to do this?To ensure that this property was not specific to gold and that a To ensure that this property was not specific to gold and that a generalization could be made for all atoms.generalization could be made for all atoms.

Rutherford then discovered the Rutherford then discovered the protonproton, and next, working with a colleague, , and next, working with a colleague, James Chadwick (1891-1974), he discovered the James Chadwick (1891-1974), he discovered the neutronneutron as well. as well.

Models of the Atom - Models of the Atom - Niehls BohrNiehls Bohr

Models of the Atom - Models of the Atom - Niehls BohrNiehls Bohr

Developed the Developed the Bohr modelBohr model of the atom of the atom (1913) in which (1913) in which electrons are restrictedelectrons are restricted to specific energies and follow paths called to specific energies and follow paths called orbitsorbits a fixed distance from the nucleus. a fixed distance from the nucleus. This is similar to the way the planets orbit This is similar to the way the planets orbit the sun. However, electrons the sun. However, electrons do notdo not have have neat orbits like the planets.neat orbits like the planets.

Diagram of Bohr model: Diagram of Bohr model:

Quantum Mechanical ModelQuantum Mechanical Model

Quantum Mechanical ModelQuantum Mechanical Model

This is the current model of the atom. We This is the current model of the atom. We now know that electrons exist in regions now know that electrons exist in regions of space around the nucleus, but their of space around the nucleus, but their paths paths cannotcannot be predicted. The electron’s be predicted. The electron’s motion is random and we can only talk motion is random and we can only talk about the about the probability of an electronprobability of an electron being being in a certain region.in a certain region.

Sub-Atomic ParticlesSub-Atomic ParticlesEach atom contains different numbers of Each atom contains different numbers of

each of the three SUBatomic particleseach of the three SUBatomic particles

ParticleParticle SymbolSymbol ChargeCharge Molar Molar MassMass

Where Where foundfound

ProtonProton pp++ +1+1 1.007 825 1.007 825 NucleusNucleus

NeutronNeutron nn00 00 1.008 665 1.008 665 NucleusNucleus

ElectronElectron ee-- -1-1 0.000 549 0.000 549 Electron Electron CloudCloud

“A neutron walked into a bar and asked how much for a drink. The bartender replied, “For you, no charge.”

Atomic NumberAtomic Number The periodic table is organized in order of The periodic table is organized in order of increasing increasing

atomic numberatomic number..

The atomic number is the whole number that is unique The atomic number is the whole number that is unique for each element on the periodic table. for each element on the periodic table. The atomic The atomic number defines the elementnumber defines the element.. For example, if the For example, if the atomic number is 6, the element is carbon. If the atomic number is 6, the element is carbon. If the atomic number is not 6, the element is not carbon.atomic number is not 6, the element is not carbon.

The atomic number represents:The atomic number represents: the number of the number of protonsprotons in one atom of that element in one atom of that element the number of the number of electrons electrons in one atom of that element (with an ion, in one atom of that element (with an ion,

the electrons will be different)the electrons will be different)

**Therefore, **Therefore, protons = electrons in a neutral atom**protons = electrons in a neutral atom**

Atomic MassAtomic Mass

mass of an element measured in mass of an element measured in amuamu (atomic mass units)(atomic mass units)

all compared to C-12 (the mass of carbon all compared to C-12 (the mass of carbon 12, which has a mass of exactly 12 amu12, which has a mass of exactly 12 amu

listed on the periodic tablelisted on the periodic tableMass #=#of p + # of nMass #=#of p + # of n

IsotopesIsotopes Isotopes are atoms of an element with the Isotopes are atoms of an element with the same number same number

of protons but different numbers of neutrons.of protons but different numbers of neutrons. Most elements on the periodic table have Most elements on the periodic table have more than onemore than one

naturally occurring isotope.naturally occurring isotope. There are a couple of ways to represent the different There are a couple of ways to represent the different

isotopes. One way is to put the mass after the name or isotopes. One way is to put the mass after the name or symbol: Carbon-12 or C-12symbol: Carbon-12 or C-12

Another way is to write the symbol with both the mass Another way is to write the symbol with both the mass number and atomic number represented in front of the number and atomic number represented in front of the symbol:symbol:

126C

C126##

massatomic

protonsprotons areare WHITE BEANSWHITE BEANS electrons areelectrons are POPCORN KERNNELSPOPCORN KERNNELS neutrons areneutrons are RED BEANSRED BEANS

BAG # of p

# of e

# of n

Atomic #

Mass #

Element Name w/ mass #

(isotope notation)

example

atomic # = # of protons in an atommass # = # of protons + # of neutrons

3 3 4 3

+

7 Lithium- 7

Determining Average Atomic Determining Average Atomic MassMass

The atomic mass on the periodic table is The atomic mass on the periodic table is determined using a determined using a weighted averageweighted average of of all the isotopes of that atom. all the isotopes of that atom.

In order to determine the average atomic In order to determine the average atomic mass, you mass, you convert the percent abundance convert the percent abundance to a decimalto a decimal and and multiply it by the massmultiply it by the mass of of that isotope. The values for all the that isotope. The values for all the isotopes are isotopes are added to togetheradded to together to get the to get the average atomic mass. average atomic mass.

Example of Average atomic mass Example of Average atomic mass calculationcalculation

Given:Given:1212C = 98.89% at 12 amuC = 98.89% at 12 amu1313C = 1.11% at 13.0034 amuC = 1.11% at 13.0034 amu

Calculation:Calculation:

(98.89%)(12 amu) + (1.11%)(13.0034 amu) =(98.89%)(12 amu) + (1.11%)(13.0034 amu) =

(0.9889)(12 amu) + (0.011)(13.0034 amu) =(0.9889)(12 amu) + (0.011)(13.0034 amu) =

12.01 amu12.01 amu

Now you try one:Now you try one: Neon has 3 isotopes:  Neon-20 has a mass of 19.992 Neon has 3 isotopes:  Neon-20 has a mass of 19.992

amu and an abundance of 90.51%.  Neon-21 has a mass amu and an abundance of 90.51%.  Neon-21 has a mass of 20.994 amu and an abundance of 0.27%.  Neon-22 has of 20.994 amu and an abundance of 0.27%.  Neon-22 has a mass of 21.991 amu and an abundance of 9.22%.  a mass of 21.991 amu and an abundance of 9.22%.  What is the average atomic mass of neon? What is the average atomic mass of neon?

The answer is:The answer is:(0.9051)(19.992 amu) + (0.0027)(20.994 amu) + (0.0922)(0.9051)(19.992 amu) + (0.0027)(20.994 amu) + (0.0922)

(21.991 amu) = (21.991 amu) = 20.179 amu 20.179 amu

Now compare this mass for Neon to the mass on the Now compare this mass for Neon to the mass on the periodic table!periodic table!

Electromagnetic RadiationElectromagnetic Radiation

Electromagnetic radiation is a form of energy Electromagnetic radiation is a form of energy that travels through space in a wave-like that travels through space in a wave-like pattern. eg. Visible light pattern. eg. Visible light

It travels in It travels in photonsphotons, which are tiny particles of , which are tiny particles of energy that travel in a wave like pattern. energy that travel in a wave like pattern. Although we call them particles, they have no Although we call them particles, they have no mass. Each photon carries one quantum of mass. Each photon carries one quantum of energy. energy.

These photons of energy travel at the speed of These photons of energy travel at the speed of light (c) = 3.00 x 10light (c) = 3.00 x 1088 m/s in a vacuum m/s in a vacuum

What is a wave and how do we What is a wave and how do we measure it?measure it?

FrequencyFrequency (ν) – number of waves that passes (ν) – number of waves that passes a given point per second (measured in Hz)a given point per second (measured in Hz)

WavelengthWavelength (λ) – shortest distance between (λ) – shortest distance between two equivalent points on a wave (measured in two equivalent points on a wave (measured in m, cm, nm)m, cm, nm)

Electromagnetic spectrumElectromagnetic spectrum (EM) (EM) The electromagnetic spectrum shows all wavelengths of electromagnetic The electromagnetic spectrum shows all wavelengths of electromagnetic

radiation – the differences in wavelength, energy and frequency radiation – the differences in wavelength, energy and frequency differentiates the different types of radiation. differentiates the different types of radiation.

Note that as the wavelength increases, the energy and the frequency Note that as the wavelength increases, the energy and the frequency decrease. decrease.

Ground state vs. Excited stateGround state vs. Excited state Electrons generally exist in the lowest energy state Electrons generally exist in the lowest energy state

they can. We call this the they can. We call this the ground stateground state. . However, if energy is applied to the electrons, they However, if energy is applied to the electrons, they

can be “excited” to a higher energy and we call this can be “excited” to a higher energy and we call this an an excited stateexcited state..

The excited state electron doesn’t The excited state electron doesn’t stay “excited”. It will fall back to stay “excited”. It will fall back to the ground state quickly. When the ground state quickly. When the electron returns to the ground the electron returns to the ground state, energy is released in the state, energy is released in the form of light. One example of this form of light. One example of this

is lasers.is lasers.

Electrons in AtomsElectrons in Atoms

We are most concerned with electrons because We are most concerned with electrons because electrons are the part of the atom electrons are the part of the atom involved in involved in chemical reactions.chemical reactions.

Electrons are found outside the nucleus, in a Electrons are found outside the nucleus, in a region of space called the region of space called the electron cloudelectron cloud. .

Electrons are organized in Electrons are organized in energy levelsenergy levels of of positive integer value (positive integer value (n = 1, 2, 3,...).n = 1, 2, 3,...).

Within each energy level are energy Within each energy level are energy sublevelssublevels,, designated by a letter: designated by a letter: s, p, d, or fs, p, d, or f. .

Each sublevel corresponds to a certain Each sublevel corresponds to a certain electron electron cloud shapecloud shape, called an , called an atomic orbitalatomic orbital..

The The electron cloudelectron cloud is like an is like an apartment buildingapartment building..

The The energy levelsenergy levels are like are like floorsfloors in the apartment building. in the apartment building.

The The sublevelssublevels are like are like apartmentsapartments on a floor of the on a floor of the building. Just like there are building. Just like there are different sizes of sublevels, different sizes of sublevels, there are different sizes of there are different sizes of apartments: 1 bedroom, 2 apartments: 1 bedroom, 2 bedroom, etc.bedroom, etc.

The The orbitalsorbitals are like are like roomsrooms within an apartment. within an apartment.

The The electronselectrons are like are like peoplepeople living in the rooms. living in the rooms.

What do these orbitals look like?What do these orbitals look like?The The s, p, d and f orbitalss, p, d and f orbitals look different and look different and

increase in complexity (f-orbitals not shown… increase in complexity (f-orbitals not shown… they are very complex)they are very complex)

Number of electrons in each sublevel Number of electrons in each sublevel depends on number of orbitals!depends on number of orbitals!

Each Each orbitalorbital can hold a maximum of can hold a maximum of 22 electrons electrons. . An An “s” sublevel“s” sublevel contains contains 1 1 s orbitals orbital. How many total . How many total

electrons can fit in an s sublevel? electrons can fit in an s sublevel? 22 A A “p” sublevel“p” sublevel contains contains 33 p orbitals p orbitals. How many total . How many total

electrons can fit in a p sublevel? electrons can fit in a p sublevel? 66 A A “d” sublevel“d” sublevel contains contains 55 d orbitals d orbitals. How many total . How many total

electrons can fit in a d sublevel? electrons can fit in a d sublevel? 1010 An An “f” sublevel“f” sublevel contains contains 77 f orbitals f orbitals. How many total . How many total

electrons can fit in an f sublevel? electrons can fit in an f sublevel? 1414

The Aufbau PrincipleThe Aufbau Principle

Three rules govern the filling of atomic orbitals. Three rules govern the filling of atomic orbitals. The first is: The first is:

The The Aufbau PrincipleAufbau Principle: Electrons enter orbitals : Electrons enter orbitals of lowest energy first. The Aufbau order lists of lowest energy first. The Aufbau order lists the orbitals from lowest to highest energy: the orbitals from lowest to highest energy: (“Aufbau” is from the German verb (“Aufbau” is from the German verb aufbauenaufbauen: : to build up)to build up)

1s1s22 2s 2s22 2p 2p66 3s 3s22 3p 3p66 4s4s22 3d 3d1010 4p 4p66 5s 5s22 4d 4d1010

5p5p66 6s 6s22 4f 4f1414 5d 5d1010 6p 6p66 7s 7s22 5f 5f1414 6d 6d1010

The Pauli Exclusion Principle The Pauli Exclusion Principle

An atomic orbital may hold at most An atomic orbital may hold at most 2 2 electrons, and they must have opposite electrons, and they must have opposite spins (called paired spins). spins (called paired spins).

When we draw electrons to show these When we draw electrons to show these opposite spin pairsopposite spin pairs, we represent them , we represent them with arrows drawn in opposite directions.with arrows drawn in opposite directions.

Hund’s Rule Hund’s Rule

When electrons occupy orbitals of equal When electrons occupy orbitals of equal energy (such as three p orbitals), one energy (such as three p orbitals), one electron enters each orbital until all the electron enters each orbital until all the orbitals contain one electron with spins orbitals contain one electron with spins parallel (arrows pointing in the same parallel (arrows pointing in the same direction). Second electrons then add to direction). Second electrons then add to each orbital so that their spins are paired each orbital so that their spins are paired (opposite) with the first electron in the (opposite) with the first electron in the orbital. orbital.

An An electron configuration electron configuration uses the uses the Aufbau order to show how electrons are Aufbau order to show how electrons are distributed within the atomic orbitals. distributed within the atomic orbitals.

How to read a segment of an electron How to read a segment of an electron configuration: configuration:

Example Example 33pp66

3 = energy level3 = energy level

p = sublevelp = sublevel66 = # of electrons = # of electrons

Now, let’s look at how to put these together Now, let’s look at how to put these together for a specific element!for a specific element!

sp

d

f

12

3

4

Electron ConfigurationsElectron Configurations

This is one way to represent the electrons of an This is one way to represent the electrons of an atom. We will try a few together:atom. We will try a few together:

ElementElement Total # of Total # of electronselectrons

Electron ConfigurationElectron Configuration

carboncarbon

fluorinefluorine

magnesiummagnesium

argonargon

66

1818

991s1s22 2s 2s22 2p 2p66 3s 3s22

1s1s22 2s 2s22 2p 2p22

1s1s22 2s 2s22 2p 2p66 3s 3s22 3p 3p66

1122

1s1s22 2s 2s22 2p 2p55

Orbital DiagramsOrbital Diagrams Orbital diagrams show with arrow notation how Orbital diagrams show with arrow notation how

the electrons are arranged in atomic orbitals for a the electrons are arranged in atomic orbitals for a given element. given element.

ElementElement Total # of Total # of electronselectrons

Orbital DiagramOrbital Diagram

carboncarbon

fluorinefluorine

magnesiummagnesium

argonargon

↑↓ ↑↓ ↑↓↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓1s 2s 2p 3s 3p1s 2s 2p 3s 3p1818

↑↓ ↑↓ ↑↓↑↓ ↑ ↑ ↑ ↑ ..1s 2s 2p1s 2s 2p

↑↓ ↑↓ ↑↓↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓.. 1s 2s 2p 3s1s 2s 2p 3s

↑↓ ↑↓ ↑↓↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ..1s 2s 2p1s 2s 2p

1212

99

66

Valence electronsValence electrons Electrons in the Electrons in the outer energy levelouter energy level of an atom. They of an atom. They

are like the front lines of an army, because they are are like the front lines of an army, because they are the ones involved in chemical reactions (valence the ones involved in chemical reactions (valence electrons get shared or transferred during reactions). electrons get shared or transferred during reactions).

The number of valence electrons that an atom has is The number of valence electrons that an atom has is directly responsible for the atom’s chemical behavior directly responsible for the atom’s chemical behavior and reactivity. and reactivity.

We can represent the number of valence electrons We can represent the number of valence electrons pictorially by drawing the electrons around the pictorially by drawing the electrons around the symbol in a “dot diagram”. The electrons are drawn symbol in a “dot diagram”. The electrons are drawn in on each side of the symbol and are not paired up in on each side of the symbol and are not paired up until they need to be. until they need to be.

Eg. Eg. . . BeBe . .

Element Electron Configuration # Valence Electrons

Electron Dot Structure

Li

Be

B

C

N

O

F

Ne

. B .

. Be .

Li.11s2 2s1

1s2 2s2

1s2 2s2 2p1

1s2 2s2 2p2

1s2 2s2 2p3

1s2 2s2 2p4

1s2 2s2 2p5

1s2 2s2 2p2

2

3

4

5

6

7

8

.. C .

.. N :

.: O :

..: F :

< ..: Ne :

The Periodic TableThe Periodic Table

The rows on the periodic table are called The rows on the periodic table are called periodsperiods

The columns on the periodic table are called The columns on the periodic table are called groups or familiesgroups or familiesElements within a group or a family have similar Elements within a group or a family have similar

reactivity. What do you know about all elements reactivity. What do you know about all elements in a period that could explain this?in a period that could explain this?

They have the same number of valence They have the same number of valence electronselectrons

Since many of the families on the periodic Since many of the families on the periodic table have such similar properties, they table have such similar properties, they some have specific names that you need some have specific names that you need to know. Get out your periodic table and to know. Get out your periodic table and label each section as we look at them label each section as we look at them together. together.

Alkali Metals are group 1 and are the Alkali Metals are group 1 and are the most reactive metals. They form +1 most reactive metals. They form +1 ions by losing their highest energy sions by losing their highest energy s11 electron. 1 valence electron.electron. 1 valence electron.

Alkaline Earth Metals are in group 2. Alkaline Earth Metals are in group 2. the form 2+ ions by losing both of the the form 2+ ions by losing both of the electrons in the highest energy s electrons in the highest energy s orbital. 2 valence electrons.orbital. 2 valence electrons.

Halogens are in group 17 and they are the Halogens are in group 17 and they are the most reactive nonmetals. The form -1 ions most reactive nonmetals. The form -1 ions by gaining 1 electron to fill the highest by gaining 1 electron to fill the highest energy p orbital. They have 7 valence energy p orbital. They have 7 valence electrons.electrons.

Noble Gases are in group 18. They do not Noble Gases are in group 18. They do not form ions because they have a full outer form ions because they have a full outer shell of electrons and do not need any shell of electrons and do not need any more electrons. They do not form more electrons. They do not form compounds.8 valence electronscompounds.8 valence electrons

The transition metals include groups 3 The transition metals include groups 3 through 12 and these metals all lose through 12 and these metals all lose electrons to form compoundselectrons to form compounds