Electron ConfigurationChapter 5 Section 3

1. You need this to see!Sodium + Titanium + Rhenium 2. You or meSulfur + Nitrogen + Phosphorous + Oxygen + Erbium 3. Vacation homeCalcium + Indium + Boron 4. Don’t gamble on this one!Erbium + Polonium + Potassium

Electron Configuration

Electron Configuration – the arrangement of electrons in an atom

Electrons tend to assume the arrangement that gives them the lowest energy possible, due to the fact that low energy systems are more stable

Three Rules to follow: Aufbau principle; Pauli exclusion principle; and Hund’s Rule

Aufbau Principle

Each electron occupies the lowest energy orbital available

Pauli Exclusion Principle

A maximum of two electrons can occupy a single atomic orbital, but only if the electrons have opposite spins

Hund’s Rule

Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with the opposite spin can occupy the same orbital

Which of the following is correct?

Which of the following is correct?

Using the periodic table as a key

What block/energy level do the following elements belong?

RuOBrCsNpAr

4d2p4p6s5f3p

What is the electron configuration for Be?

What is the electron configuration for N?

What is the electron configuration for Mg?

What is the electron configuration for S?

What is the electron configuration for K?

What is the electron configuration for Ni?

Homework 10/27/14

Do the electron configuration for elements 1 – 18 in your notes.

Electron Configuration Notation

Designates the principal energy level, the energy sublevel (associated with each orbital), and the number of electrons in the sublevel

Sodium: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑_

1s 2s 2p 3s

Sodium: 1s2 2s2 2p6 3s1

Write the Electron configuration notation for the following:

ZrCeNiSeSr

HW: Using your homework from last night write the notation for elements 1 – 18 H

He

Li

Be

B

C

N

O

F

Ne

Na

Mg

Al

Si

P

S

Cl

Ar

Noble Gas Notation

Noble gasses are the last column of the periodic table

Full p-shells = Very stable Noble Gas Notation uses bracketed symbols to

consolidate notation Notation for Na: 1s2 2s2 2p6 3s1

Noble Gas Notation for Na: [Ne] 3s1

Noble Gas Notation

Use the Noble gas before the element you are looking at

Start electron configuration after that noble gas

Example: For Mo, Kr ends in 4p6 so you start with 5s[Kr] 5s2 4d4

What is the noble gas notation for the following:

BiRbVSiRu