Electron Configuration Lesson

Electron Configuration and Valence Electrons

Please take notes and write down areas you are having problems with.

Learning Objectives revisited...

Can you ... ?

• Determine # of electrons in an atom based on Atomic Number

• Recognize simple electron configurations based on format “#-#-#”

• Locate the electron configuration of an element on the Periodic Table

• Explain electron energy levels (aka “shells”).

• Recall the maximum number of electrons for shells 1, 2, and 3

• Define the term valence electrons & Identify # of valence e^-s

Each orbital can contain up to 2 electrons

• s orbitals can hold a total of 2 electrons (1 orbital)

• p orbitals can hold a total of 6 electrons (3 orbitals)

• d orbitals can hold a total of 10 electrons (5 orbitals)

• f orbitals can hold a total of 14 electrons (7 orbitals)

The blocks of the periodic table

As you can see here the "s" block is shown on the left in pink, the "p" block is on the right in orange, the "d" block is in the middle shown in blue, and the "f" block is shown below in yellow.

Think about it....

The s block contains 2 columns and the "s" orbitals can contain 2 electrons. The p block contains 6 columns and the "p" orbitals can contain up to 6 electrons. The d block contains 10 columns and the the "d" orbitals can contain up to 10 electrons! (This is NOT a coincidence!)

Multiple Choice

If the f block contains 14 columns, then it would make sense that an f orbital can hold up to _____ electrons.

• 2

• 5

• 7

• 14

Orbital filling

Electrons fill these orbitals in a way that allows them to take the easiest root possible. The LOWEST energy levels are filled first.

Orbital filling cheat sheet

You copied this orbital filling diagram cheat sheet in your notes. It is important that you always use it to fill electrons into orbitals when completing electron configurations.

Multiple Choice

Using your orbital filling cheat sheet, tell me which orbital fills after the 2 p orbital is full.

• 3p

• 3s

• 2s

• 1p

Multiple Choice

Using your orbital filling cheat sheet, which orbital fills after the 4s orbital?

• 4p

• 5s

• 3d

• 4f

Multiple Choice

The electron configuration of an element is 1s² 2s² 2p^1. How many more electrons does the element need to satisfy the octet rule?

• 2

• 3

• 5

• 8

Multiple Choice

Which of the following could have the electron configuration 1s²2s²2p⁶3s²3p⁶
1.Cl^-
2. K⁺
3. Al³⁺

• 1 only
• 2 only
• 1 and 2
• 1, 2, and 3

Multiple Choice

What is the electron configuration for Arsenic?

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p³
• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³
• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4d¹⁰ 4p³

Multiple Choice

The octet rule states that chemical compounds tend to form so that each atom has an octet of electrons in

• its p orbitals
• its d orbitals 
• its highest occupied energy level
• the 1s orbital

Multiple Choice

The electron configuration for aluminum is-

• 1s² 2s² 2p⁶ 3s² 2d¹.

• 1s² 2s² 2p⁹.

• 1s² 2s² 2p⁶ 3s² 3p¹.

• 1s² 2s² 2p³ 3s² 3p³ 3d¹.

Multiple Choice

What is the electron configuration for nitrogen? 

• 1s² 2s³ 2p²
• 1s² 2s² 2p³
• 1s² 2s² 2p² 3s¹
• 1s² 2s³ 2p¹

Multiple Choice

Which family is the MOST reactive on the Periodic Table?

• Alkali Metals

• Alkaline Earth Metals

• Halogens

• Noble Gases

Multiple Choice

Which of the following is an f block element?

• Ar

• La

• Cu

• Mg

Multiple Choice

What is this element?

1s²2s²2p⁶3s²3p⁶

4s²3d¹⁰4p⁶

• Argon (Ar)

• Krypton (Kr)

• Selenium (Se)

• Bromine (Br)

Multiple Choice

Which is the electron configuration for an Oxygen (O) atom?

• 1s²2s²2p⁶3s²3p⁶4s²

• 1s²2s²2p⁴

• 1s²2s²2p⁶

• 1s²2s²2p⁶3s²3p⁶

Multiple Choice

If an atom of Fluorine has 10 neutrons, which of the following is FALSE?

• The mass number is 19.

• There are 10 total electrons.

• There are 7 valence electrons.

• There are 9 protons.

Multiple Choice

What element is:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰

?

• Cu

• Ag

• Au

• Zn

• Cd

Multiple Choice

What element is

1s² 2s² 2p⁶ 3s² 3p⁵

?

• O

• F

• Cl

• Br

Multiple Choice

What element is

1s² 2s² 2p²

?

• B

• C

• N

• F

Multiple Choice

What does Hund's rule states ?

• states that single electrons electrons with the same spin must occupy each-energy orbital before additional electrons with opposite spins can occupy the same orbitals
• states that each electron occupies the lowest energy orbital available
  
• states that a maximum of two electrons can occupy a single atomic orbital, but if only if the electros have opposite spins

Multiple Choice

What does Pauli exclusion principle state ?

• states that each electron occupies the lowest energy orbital available
• states that a maximum of two electrons can occupy a single atomic orbital, but if only if the electros have opposite spins
• states that single electrons electrons with the same spin must occupy each-energy orbital before additional electrons with opposite spins can occupy the same orbitals

Multiple Choice

Electrons occupy orbitals of lowest energy first is part of what electron configuration rule?

• Hund’s Rule
• Aufbau Principle
  
• Pauli Exclusion Principle

Multiple Choice

What do you start electron configuration with?

• 1s²
• 1d¹⁰
• 1f¹⁴
• 1p⁶

Multiple Choice

How many valence electrons does Chlorine have?

• 5
• 2
• 7
• 5

Multiple Choice

What atom matches this electron configuration?
1s² 2s² 2p⁶ 3s²

• Neon
• Magnesium
• Aluminum
• Potassium