View
215
Download
0
Category
Preview:
Citation preview
The AtomThe Atom
The AtomThe Atom
The atom has The atom has three parts:three parts:
1)1) ProtonsProtons
2)2) NeutronsNeutrons
3)3) ElectronsElectrons
ProtonsProtons Protons:Protons:
1)1) Found in the nucleusFound in the nucleus
2)2) Mass: one (1) Atomic Mass UnitMass: one (1) Atomic Mass Unit
3)3) have a (+) positive charge, have a (+) positive charge,
11 PPROTON = 1 ROTON = 1 PPOSITIVEOSITIVE ChargeCharge
Protons (Cont’d)Protons (Cont’d) On the periodic table, each element is On the periodic table, each element is
numbered. This number equals the numbered. This number equals the number of number of ProtonsProtons in the nucleus. in the nucleus.
NeutronsNeutrons
Also found in the nucleus.Also found in the nucleus. Mass: one (1) Atomic Mass Unit.Mass: one (1) Atomic Mass Unit. They have They have NONO charge. charge. NeutrNeutron on = =
NeutrNeutralal
ElectronsElectrons Found around the nucleus (like planets around the Found around the nucleus (like planets around the
Sun)Sun) An An ElectronElectron’s mass is almost nothing…almost’s mass is almost nothing…almost Have a negative (-) chargeHave a negative (-) charge
EELLEECTRONS = NCTRONS = NEEGATIVGATIVEE
Standard Atomic NotationStandard Atomic Notation
Be
9
4
Mass Number = mass of all the protons and neutrons in the nucleus
Atomic Number = number of protons in the nucleus and the number of electrons orbiting the nucleus
Element Symbol – eg. Beryllium
To find the number of neutrons in the nucleus, subtract atomic number from mass number. There would be 9 – 4 or 5 neutrons in a Beryllium atom
RememberRemember
The periodic table is organized by The periodic table is organized by atomic number (the number of atomic number (the number of protons the element has in its protons the element has in its nucleus)nucleus)
Protons are + and electrons are - Protons are + and electrons are - The number of protons = the number The number of protons = the number
of electrons (positives = negatives)of electrons (positives = negatives)
Let’s try some!Let’s try some!
Have your periodic table readyHave your periodic table ready How many protons, neutrons and How many protons, neutrons and
electrons in one atom of:electrons in one atom of: Hydrogen?Hydrogen? Carbon?Carbon? Beryllium?Beryllium? Calcium?Calcium? Fluorine?Fluorine?
1 p+, 1 e-, 0 n
20 p+, 20 e-, 20 n
6 p+, 6 e-, 6 n4 p+, 4 e-, 5 n
9 p+, 9 e-, 10 n
Bohr-Rutherford DiagramsBohr-Rutherford Diagrams
Named after the Named after the work done by Neils work done by Neils Bohr and Ernest Bohr and Ernest Rutherford (nobody Rutherford (nobody before them gets any before them gets any respect!)respect!)
Flattened model of Flattened model of the inside of an atomthe inside of an atom
Unique for each atomUnique for each atom
Electron ShellsElectron Shells
Nucleus12 P12 N
1 2
First Shell, maximum 2 electrons
2 elements in first row (period)
Why only 2 in the first shell?Why only 2 in the first shell?
Electron ShellsElectron Shells
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
Second Shell,Maximum 8 electrons
Why 8 in the second shell?Why 8 in the second shell?
8 elements in second period
Electron ShellsElectron Shells
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
11 12
Third shell, max # 8 electrons
Note: Magnesium only needs 2 electrons in this shell because it has 12 total
Bohr-Rutherford DiagramsBohr-Rutherford Diagrams
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
11 12
Eg. Magnesium
Guess this elementGuess this element
82 protons = element 82 which is LEAD82 protons = element 82 which is LEAD
The Noble GasesThe Noble Gases
Column to the far right of the periodic Column to the far right of the periodic table, He, Ne, Ar, Kr, Xe, & Rntable, He, Ne, Ar, Kr, Xe, & Rn
Nucleus2 P2 N
1 2
Nucleus10 P10 N
1 2
3 4
5
6
7
8
9
10
So, how would Magnesium look like So, how would Magnesium look like Neon?Neon?
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
11 12
Magnesium Neon
Nucleus10 P10 N
1 2
3 4
5
6
7
8
9
10
So, if Mg lost two So, if Mg lost two Electrons, Electrons, but still had the but still had the same number of same number of ProtonsProtons, what is its , what is its Charge?Charge?
+2+2
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
ChargesCharges
The outer The outer electronselectrons on an atom are on an atom are called: called: ValenceValence electronselectrons. .
Atoms want a Atoms want a Bohr-Rutherford Bohr-Rutherford Diagram Diagram that look like the Noble that look like the Noble Gases because… Gases because… have the most stable structurehave the most stable structure Won’t react when mixedWon’t react when mixed
Usually, this means the atom ends up Usually, this means the atom ends up with a with a Charge.Charge.
FluorineFluorine
What does F need to look like a Noble gas?What does F need to look like a Noble gas? If we add one If we add one Electron,Electron, what will the what will the
Charge Charge of the atom be?of the atom be? - 1- 1
Nucleus9 P9 N
1 2
3 4
5
6
7
8
9
10
IonsIons Ion=Ion= a a Charged Charged atom in which the number atom in which the number
of of ELECTRONS (-)ELECTRONS (-) is different from the is different from the number of number of PROTONS (+)PROTONS (+)..
Ionic Charge= Ionic Charge= is the number of is the number of positive (+) positive (+) or or negative (-) negative (-) Charges Charges on an atom. Ex: Mgon an atom. Ex: Mg+2+2
Nucleus12 P12 N
1 2
3 4
5
6
7
8
9
10
GroupsGroups
Mg
Nucleus12 P12 N
12
3 4
5
6
7
8
9
10
11 12
1 2
3 4
Nucleus4 P4 N
Be (Berylium)
So…So…
Even though each element has a Even though each element has a different # of different # of PROTONS PROTONS and and ELECTRONSELECTRONS, each element in a group , each element in a group has a similar has a similar Bohr-Rutherford DiagramBohr-Rutherford Diagram
This means they want to This means they want to gaingain or or loselose the same number of the same number of Electrons.Electrons.
It also means elements in a Group will It also means elements in a Group will react similarly in Chemical Reactionsreact similarly in Chemical Reactions
Recommended