POST TRANSITION NOBLE GASSES HALOGENS...TRANSITION METALS LANTHANIDES ACTINIDES POST TRANSITION...

TRANSITION METALS

LANTHANIDES

ACTINIDES

POST TRANSITION METALS NON METALS

NOBLE GASSES

HALOGENS

SEMI METALS

Hydrogen is considered to be a group on its own

ALKALI METALS

ALKALINE EARTH METALS

TRENDS OF THE PERIODIC TABLE Chemistry 11Atomic Theory

WHICH ONE OF THE FOLLOWING ARE BIGGER?

1.Li or Na2.Cs or Rb3.F or Cl4.Pb or Si

WHICH ONE OF THE FOLLOWING IS BIGGER?

1. Na or Mg2. Na or Cl

TRENDS OF THE PERIODIC TABLE

3 factors are discussed when explaining above trends1. Nuclear Charge2. Shielding Electrons3. Number of Shells

We will be discussing the following trends1. Atomic Radius2. Ionization Energy3. Electronegativity

NUCLEAR CHARGE - LEFT TO RIGHT

vAtomic # increases = # of protons increase (more +ve charges)

Across The Periodic Table

OVERALL Pull on electrons due to nuclear charge INCREASES

-

++-

-+

-- -

-Electrons experience pull force from the positive protons in the nucleus.

NUCLEAR CHARGE – TOP TO BOTTOM

v Atomic # increases = # of protons increase (more +ve charge)

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OVERALL Pull on electrons due to nuclear charge INCREASES

SHIELDING ELECTRONS

----5P6N

Boron

-

SHIELDING ELECTRONS

----5P6N

Boron2 Shielding electrons

Outer Electrons being blocked by the inner electrons from nuclear charge

What are shielding electrons?

Electrons in the lower shells that block the pull of the protons.

Campfire Analogy – If someone is between you and the fire, you feel less heat.

-

SHIELDING ELECTRONS – LEFT TO RIGHT

-

--

-- -

-

9P10N

-

Beryllium 2 Shielding electrons

Fluorine2 Shielding electrons

--- 4P

5N-

OVERALL Number of Shielding electrons STAY THE SAME

Across The Periodic Table

SHIELDING ELECTRONS – TOP TO BOTTOM

10 Shielding electrons

18 Shielding electrons

OVERALL Number of Shielding electrons

INCREASES

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NUMBER OF SHELLS – LEFT TO RIGHT

Number of shells stay the SAME going across

Across The Periodic Table

NUMBER OF SHELLS – LEFT TO RIGHT

Number of shells INCREASE going down

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ATOMIC RADIUS

ATOMIC RADIUS – LEFT TO RIGHT

Nuclear Charge

• Increases • More protons pull electrons closer ∴ Atom is SMALLER

Number of Shells

• Stays the same in the same period

∴ NO CHANGE

OVERALL Atomic Radius DECREASES Going Across

Shielding Electrons

• Stay the same in the same period

∴ NO CHANGE

Across The Periodic Table

ATOMIC RADIUS – TOP TO BOTTOM

Nuclear Charge

• Increases• More protons pull electrons closer

∴ Atom is SMALLER

Number of Shells

• Increase going down

∴ Atom is LARGER

OVERALL Atomic Radius INCREASES Going Down

Shielding Electrons

• Increases• More electrons blocking the pull

of outer electrons.∴ Atom is LARGER

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Ato

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Atomic Radius Decreases

EXERCISE What is the largest atom in period 4?• Potassium

What is the largest and the smallest atom in group 2?• Largest – Radium • Smallest – Beryllium

Which is larger?• F or B?• Ba or Be?• Sr or P?

B

Ba

Sr

Open the refrigerator , put the giraffe in and close the door

Open the refrigerator , take out the giraffe put in the elephant and close the door

The Elephant

You swim across. All the crocodiles are attending the animal conference

JIGSAW ACTIVITY

Sitting in groups, you will be assigned one of three cards (Nuclear Charge, Shielding Electrons, and Number of

Shells.

Try to come up with answers to the questions individually and then discuss with group members.

JIGSAW ACTIVITY

Find two other classmates that have different cards than yours.

Take turns to explain your answers. Do the backside of Periodic Table Trends worksheet

JIGSAW ACTIVITYIn your groups come up with the following conclusions

OVERALL Atomic Radius INCREASES or DECREASES going across?

OVERALL Atomic Radius INCREASES or DECREASES going down?

ATOMIC RADIUS – IONS

CATIONS (+ve)

Lose electrons: Inter-electron repulsion (repulsion between electrons) decreases.

∴ Cation is SMALLER than its Atom

ANIONS (-ve)

Gain electrons: Inter-electron repulsion (repulsion between electrons) increases.

∴ Anion is LARGER than its Atom

IONIZATION ENERGYIt ALWAYS requires energy to remove an electron from an atom!!!

We ae breaking the electron’s attraction towards the nucleus.

DEFINITION

Ionization energy Energy required to remove an electron from the outer shell

IONIZATION ENERGY – LEFT TO RIGHT

Predict how nuclear charge, shielding electrons and number of shells would influence ionization energy going across the periodic table. Explain your answer.

Across The Periodic Table

IONIZATION ENERGY– LEFT TO RIGHT

Nuclear Charge

• Increases • More protons pull electrons closer• Harder to remove an electron∴ Ionization Energy INCREASES

Number of Shells

• Stays the same in the same period

∴ NO CHANGE

OVERALL Ionization Energy INCREASES

Shielding Electrons

• Stay the same in the same period

∴ NO CHANGE

Across The Periodic Table

IONIZATION ENERGY – LEFT TO RIGHT

Predict how nuclear charge, shielding electrons and number of shells would influence ionization energy going down the periodic table. Explain your answer.

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IONIZATION ENERGY– TOP TO BOTTOMNuclear Charge

• Increases • More protons pull electrons closer. • Harder to remove an electron.

∴ Ionization Energy INCREASES

Number of Shells

• Increases• Electrons move farther away from

the nucleus.• Easier to remove an electron.∴ Ionization energy DECREASES

OVERALL Ionization Energy DECREASES

Shielding Electrons

• Increases• More electrons block the pull of outer

electrons.• Easier to remove an electron.∴ Ionization Energy DECREASES

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Ioni

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Ionization Energy Increases

EXERCISE

What atom has the highest Ionization Energy?• He

Which has the lowest Ionization energy?­ Fe or B?­ Ba or Ba2+?­ Sr or P?

B

Ba

Sr

ELECTRONEGATIVITY DEFINITION

Ability of an atom to attract an electron from another atom.

If an atom has high electronegativity, it strongly attracts electrons from other atoms and might even remove the electron completely.

ELECTRONEGATIVITY – LEFT TO RIGHT

Predict how nuclear charge, shielding electrons and number of shells would influence electronegativity going across the periodic table. Explain your answer.

Across The Periodic Table

ELECTRONEGATIVITY– LEFT TO RIGHT

Nuclear Charge

• Increases • More protons, attract electrons more.• Atom is strong! • Easier to remove electron from another atom∴ Electronegativity INCREASES

Number of Shells

• Stays the same in the same period

∴ NO CHANGE

OVERALL Electronegativity INCREASES

Shielding Electrons

• Stay the same in the same period

∴ NO CHANGE

Across The Periodic Table

ELECTRONEGATIVITY – LEFT TO RIGHT

Predict how nuclear charge, shielding electrons and number of shells would influence electronegativity going down the periodic table. Explain your answer.

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ELECTRONEGATIVITY– TOP TO BOTTOMNuclear Charge

• Increases • More protons attract electrons more.• Atom is Strong!• Easier to pull an electron from another atom.

∴ Electronegativity INCREASES

Number of Shells

• Increases• Electrons are farther away from the proton.• Atom is weak!• Harder to pull electron from another atom.∴ Electronegativity DECREASES.

OVERALL Electronegativity DECREASES

Shielding Electrons

• Increase • Block the charge of protons.• Atom is weaker.• Harder to pull electron from another

atom.∴ Electronegativity DECREASES

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Electronegativity Increases

MEASURING ELECTRONEGATIVITY

We use Pauling Scale to quantify electronegativity.

Highest electronegativity (value of 4) is assigned to Fluorine.

Values range down to Cs and Fr, which are the lease electronegative atoms (value of 0.7)

ELECTRONEGATIVITY AND IONIZATION ENERGY

If an atom has high electronegativity, it will also have a high ionization energy!

An atom that is strong, will not give away its electron easily!!!

HOMEWORK