Warmup1) Are magnesium and calcium in the same group, or the same period?2) Are beryllium and oxygen in the same group, or the same period?3) Write the electron configuration for magnesium. Identify the energy level and orbital for the highest-energy electron.

Periodic Table Trendsand Bonding

Today we will learn about supervising your children at the grocery store, as well as proper ways to share popcorn, and

the land of rainbows and unicorns

1) # protons in the nucleus

2) Distance of e-from the nucleus

3) Shielding by inner e-

Factors Influencing Periodic Trends:

As you go down a group, As you go down a group, atomic radius _______ atomic radius _______ because ____________because ____________

increases: each atom has an additional energy level

HLi

Na

K

Rb

Atomic Radius:the distance between the atomic nuclei and the furthest electron orbital

Across a period, atomic radius _______ because ______________________

decreases: even though there are additional electrons, the number of energy levels are the same. The nuclear charge (# protons increases, so the e- cloud is pulled in closer

Na Mg Al Si P S Cl Ar

Which has the largest A.R, Mn, Tc, Re?•All are in same group•AR increases down a group

Rhenium has the largest AR because it has more layers of electrons (closest to Fr!)

Which has the smallest A.R, Ge, As, Se?•All are in the same period•AR increases right to left across a period

Selenium has the smallest AR; more + charge inside the nucleus, holds its e- more tightly than As and Se

2 Questions, 2 Minutes!

Francisco Francium: rich chunky guy, easygoing and generous

Florence Fluorine:skinny, short, angry, demanding

Li

+++

Be

++++

B +++++

ionization energy is the energy required to remove an electron from a neutral atom

IE _____ as you go across a period because ____

increases: nuclear charge increases

IE _____ as you go down a group due to ____

decreases: increased shielding and larger AR

Firs

t Io

niza

tion

ener

gy

Atomic number

The IE trend is actually a little bit crazy, due to the stability of half-filled p orbital or a full s orbital.

The d orbital electrons shield each other significantly, so there is little change

Find the weird stuff.

It measures how strongly an atom attracts SHARED electrons.

Electronegativity is similar to IE and follows the same general trend as IE

2 Questions, 2 Minutes!Which element has the lowest ionization

energy: B, O, or C?

Which element has the highest electronegativity: Ba, Mg, or Ca?

BORON. Why?

MAGNESIUM! Why?

Which of the following has the lowest electronegativity?

A. P

B. Mg

C. Cl

D. Na

E. Si

Which of the following atoms has the highest IE?A. Sb

B. P

C. As

D. Al

E. Si

Which of the following is ranked in order of largest to smallest atomic radius?A. Se > Te > I

B. Se < Te < I

C. Se < I < Te

D. I < Se < Te

A change in period is way more significant

than a change in group (for ANY of the properties).

Back to Atomic Radius: ion vs atom size

Which is larger, the lithium atom (Li) or the lithium ion (Li+)?

Which is larger, the flourine atom (F) or the flouride ion (F-)?

Why? Discuss.

Configuration of Ions

• Na is 1s22s22p63s1

• Forms a +1 ion: 1s22s22p6

• (same as neon)

Account for the trend in ion size shown as you go across a period:

• Cations have less energy levels than the anions in the same period

• C4+ : full first energy level• N3- : full first and second energy levels• O2- : same # e- as nitrogen atom but more protons

(stronger nuclear charge), pulls e- in closer

Li+1

Be+2

B+3

C+4

N-3O-2 F-1

Atoms don’t always share their e- equally, so bonds can be:

Chemical Bond: force that holds 2 atoms together

Ionic• Electrons are given

away; cations and anions

attracted to each other

Polar Covalent• Electrons are unequally shared• one atom “hogs” the electrons more and has a

slightly negative charge

Nonpolar Covalent• Electrons EQUALLY shared between atoms.

What type of bond do Na and N have? Calculate the difference in EN between

the two atoms in the bond!

(metal/nonmetal)(two nonmetals)

3.0 – 0.9 = 2.1

2.1 >1.7……..ionic bond

nonpolar covalent polar covalent ionic

0.0 0.3 1.7 3.3

What kind of bond exists between two atoms of chlorine?

3.0 – 3.0 = 0……. NON polar COVALENT*note the even distribution of the electron cloud

COVALENT BONDS

Single: 2 atoms share 2 e- (1 pair)

Double: 2 atoms share 4 e- (2 pairs)

Triple: 2 atoms share 6 e- (3 pairs)

Cl Cl

What type of bond will form between H and O?

1.4 polar covalentThe more EN atom (O) will get the e-’s for a greater amount of time and thus be slightly more negative

You may either put lowercase delta negative (δ-) near the most EN atom in the bond to indicate a slight negative charge, or draw arrows toward the most EN atom, or both

δ+δ-

-