Warm Up

1. Write the equation for the release of a beta particle by Pb-211

2. Write the equation for Po-219 undergoing 1 alpha decay.

Warm Up

1. Write the equation for the release of a beta particle by Pb-211

Pb e + Bi

2. Write the equation for Po-219 undergoing 1 alpha decay.

Po He + Pb

211 0

-182

211

83

822

4219

84

215

Electron configuration and periodic trends

- Electrons occupy orbitals around the nucleus

- Electrons in a particular path have fixed energy

• The energy level of an electron is the region around the nucleus where the electron is likely to be moving.

• Principle energy levels are assigned values in order of increasing energy

• n = 1, 2, 3, 4

• Each energy level can be divided into sublevels

Energy Level (n)

# e- Sublevel

n = 1 2 1s

n = 2 8 2s 2p

n = 3 18 3s 3p 3d

n = 4 32 4s 4p 4d 4f

• The sublevels each hold a set amount of electrons

• s - can hold 2 e-• p - can hold 6 e-• d - can hold 10 e- • f - can hold 14 e-

Orbital Diagram

Order in which electrons fill the sub orbitals

This diagram represents the electron configuration for Carbon

This diagram represents the electron configuration for Carbon

The red arrows represent the possible locations of electrons shared with carbon when in a covalent bond.

Lets Find the Orbital Diagram for Mg s - can hold 2 e-p - can hold 6 e-d - can hold 10 e- f - can hold 14 e-

Mg – Magnesium has how many total electrons?

12

Next, we set up our diagram:

Lets Find the Orbital Diagram for Mg s - can hold 2 e-p - can hold 6 e-d - can hold 10 e- f - can hold 14 e-

Mg – Magnesium has how many total electrons?

12

Next, we set up our diagram:

Lets Find the Orbital Diagram for Mg

Mg 1s22s22p63s2

s - can hold 2 e-p - can hold 6 e-d - can hold 10 e- f - can hold 14 e-

Review:

• What is a valence electron?• How many valence electrons are found in

Oxygen?

Periodic Trends

• Atomic Size• Ionization energy• Electronegativity

Atomic Size (Radius)

• Increases down a group• Decreases left to right

Atomic Size (Radius)

• Increases down a group• Decreases left to right

Atomic Size (Radius)

• Increases down a group• Decreases left to right

Ionization Energy

• The energy required to overcome the attraction of the nuclear charge and remove an electron from a gaseous atom

– Increases left to right across a period– Decreases down a group

What do you notice about the elements at the peaks and valleys?

Electronegativity• The tendency for the atoms of an element to

attract electrons when they are chemically combined with atoms of another element– Increases left to right across a period– Decreases going down a group

Let’s practice!!!