Valence Electrons & Bohr Diagrams

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Slide 1

Valence Electrons & Bohr Diagrams

Slide 2

Atomic Structure

Atoms have a nucleus that contains Protons and Neutrons

Electrons are contained in shells that surround the nucleus

An atom is made of mostly empty space

Protons have a positive charge

Electrons have a negative charge

Neutrons are Neutral

Slide 3

Valence Electrons

Each electron shell can hold a certain number of electrons

Electron shells are filled from the inside out

Noble Gases have full outer electron shells

All other elements have partially filled outer electron shells

Slide 4

Valence Electrons

The electrons in the outer most electron shell are called valence electrons

The shell containing electrons that is furthest from the nucleus is called the valence shell

The number of electron shells with electrons is the same as the period number

Slide 5

Noble Gas Stability

Noble gases are usually unreactive

This is because they have full valence shells

An element with a full valence shell is a happy element 

For two atoms to join together atoms must gain, lose or share electrons

Elements with full valence shells do not easily gain or lose electrons

Slide 6

Noble Gas Stability

Atoms want to gain stability

Atoms will try to gain or lose electrons to have a full valence shell

Metals try to lose electrons

Non-Metals try to gain electrons

Slide 7

Becoming An Ion

Electrons are negatively charged

Protons are positively charged

Neutral atoms do not have a charge because the number of protons is the same as the number of electrons

When atoms gain or lose electrons they become positively or negatively charged

An atom with a charge is called an Ion

Slide 8

Bohr Models

Niels Bohr created a visual model of the atom to make them easy to understand

A Bohr Model contains a central nucleus surrounded by electron shells

For each model you state the number of protons and neutrons in the nucleus and draw a dot on the electron shells for each electron