Atomic RadiusAtomic RadiusThe The radiusradius of an of an atomatom..Periods - Periods - decreasesdecreases as you move left to as you move left to

right across the tableright across the tableWhy? Nucleus becomes more Why? Nucleus becomes more positivepositive, while , while

the electrons remain in the the electrons remain in the samesame energy level. energy level. This change causes the electrons to be This change causes the electrons to be pulled toward the nucleus making the radius pulled toward the nucleus making the radius smallersmaller..

Groups - Groups - increaseincrease as you move down a as you move down a group.group.Why? More Why? More energyenergy levelslevels are added to the are added to the

atom making it atom making it biggerbigger..

Which of the following has the Which of the following has the largest atomic radius?largest atomic radius?

F or BrF or BrAl or SAl or SNa or PNa or PLi or RbLi or Rb

Ionic RadiusIonic Radius The The radiusradius of an of an ionion.. Ion – an Ion – an atomatom with a with a negativenegative or or positivepositive charge charge

(gained or lost an electron)(gained or lost an electron) Important: When an atom Important: When an atom gains / losesgains / loses

electrons, it becomes more electrons, it becomes more negative / positivenegative / positive and then becomes and then becomes bigger / smallerbigger / smaller..

Periods – Periods – The The leftleft side has side has positively chargedpositively charged ions. ions. The The rightright side has side has negatively chargednegatively charged ions. ions. Where they meet, there is a Where they meet, there is a hugehuge jump in ionic radius. jump in ionic radius.

Groups - Groups - increaseincrease as you move down a group. as you move down a group. Why? More Why? More energyenergy levelslevels are added to the atom are added to the atom

making it making it biggerbigger..

Another way to think of it:Another way to think of it:

The more The more negativenegative the bigger; the bigger;

the more the more positivepositive the smaller the smaller

Which of the following has the Which of the following has the largest ionic radius? largest ionic radius?

SrSr+2+2 or Rb or Rb+1+1

BrBr-1-1 or F or F-1-1

TiTi+2 +2 or Seor Se-2-2

For the next two trends, For the next two trends, remember the remember the octetoctet rule. rule.

(All atoms want 8 valence (All atoms want 8 valence electrons)electrons)

Ionization energyIonization energy EnergyEnergy required to required to removeremove an electron or how an electron or how

wellwell an atom’s nucleus holds onto its an atom’s nucleus holds onto its valencevalence electrons.electrons.

Periods - Periods - increasesincreases as you move left to right as you move left to right across the tableacross the tableWhy? Why? moremore nuclear charge nuclear charge stronglystrongly hold on hold on

electronselectrons Groups - Groups - decreasedecrease as you move down a group. as you move down a group.

Why? Why? moremore electrons are electrons are furtherfurther from the nucleus from the nucleus resulting in resulting in lessless pull. pull.

This is also caused by This is also caused by electronelectron shieldingshielding - the - the blocking of the positive nucleus by inner electrons.blocking of the positive nucleus by inner electrons.

Which of the following has the Which of the following has the highest ionization energy?highest ionization energy?

N or AsN or AsB or OB or OLi or RbLi or RbBe or SrBe or Sr

ElectronegativityElectronegativityRelative Relative abilityability of an atom to of an atom to attractattract electrons in electrons in

a chemical bond.a chemical bond.Periods - Periods - increasesincreases as you move left to right as you move left to right

across the tableacross the tableWhy? Why? moremore nuclear charge nuclear charge attractattract electrons electrons

Groups – Groups – decreasedecrease as you move down a group. as you move down a group.Why? Electrons are Why? Electrons are furtherfurther from the nucleus from the nucleus

resulting in resulting in lessless attraction. attraction.Not counting the Not counting the noblenoble gasesgases (Group 8A), (Group 8A),

fluorinefluorine is the most electronegative while is the most electronegative while franciumfrancium is the least. is the least.

Which of the following has the Which of the following has the highest electronegativity?highest electronegativity?

Na or RbNa or RbB or FB or FK or CaK or CaF or IF or I