Chemistry Part II Electrons and Chemistry Part II Electrons and Bonding.Bonding.

Electrons surround the nucleus of Electrons surround the nucleus of an atom.an atom.

Electrons are Electrons are negatively charged negatively charged particles.particles.

They are responsible They are responsible for chemical reactions.for chemical reactions.

The have a very, very, The have a very, very, very, very, very, very very, very, very, very small mass.small mass.

8ft 2 ft

Electrons are found around the Electrons are found around the nucleus in clouds otherwise known nucleus in clouds otherwise known

as energy levels.as energy levels. The 1The 1stst energy level energy level

around a nucleus can around a nucleus can hold a max of 2 electronshold a max of 2 electrons

The 2The 2ndnd energy level energy level around a nucleus can around a nucleus can hold a max of 8 electronshold a max of 8 electrons

The 3The 3rdrd Energy level can Energy level can hold a max of 18 hold a max of 18 electrons.electrons.

How it worksHow it works

nucleus

Lithum has an atomic number of 3, so there are 3 protons. This means there are 3 electrons

Place electrons around the nucleus by first putting them on the first energy lever. 1st level max is two electrons. Once you hit the max go to the next level.

Electron

2nd Energy Level

1st Energy Level

You Try Magnesium it has an You Try Magnesium it has an atomic number of 12.atomic number of 12.

Nucleus

How to do it.How to do it.

Nucleus

1st level can hold a max of 2 electrons

Put two electrons on the 1st level

How to do it.How to do it.

Nucleus

1st level can hold a max of 2 electrons

2nd level can hold a max of 8 electrons

Place 8 more electrons on the 2nd level

How to do it.How to do it.

Nucleus

1st level can hold a max of 2 electrons

2nd level can hold a max of 8 electrons

3rd level can hold a max of 18, but we need to only place 2

2+8+2=12

Place 2 more electrons on the 3rd level

Answer to Magnesium it has an Answer to Magnesium it has an atomic number of 12.atomic number of 12.

Nucleus

2+8+2=12

Your turn to determine the protons, Your turn to determine the protons, neutrons, electrons and then draw neutrons, electrons and then draw

the atoms.the atoms.

9

Fluorine

F

18.99

Protons =

Neutrons =

Electrons =

BondingBonding

When atoms join together When atoms join together or bond it is due to the or bond it is due to the creation of a more stable creation of a more stable piece of matter.piece of matter. Electrons filling up the outer Electrons filling up the outer

energy levels to their energy levels to their maximum is what creates maximum is what creates stability.stability.

Outer energy levels are Outer energy levels are called valance levels.called valance levels.

Stable = outer electrons maxed on 2nd level.

8 valence electrons.

Unstable = 1 electron, when it can hold a max of 8.

1 Valence electron.

BondingBonding

There are stable atoms There are stable atoms on the periodic table, we on the periodic table, we call them the noble call them the noble gasses.gasses. Helium, neon, argon, Helium, neon, argon,

krypton, xenon, radon.krypton, xenon, radon. All of them have full All of them have full

valence levels.valence levels. Outermost levels are at Outermost levels are at

their max or full.their max or full.

Luckily not all atoms are stable so we get a Luckily not all atoms are stable so we get a variety of chemicals and two major types of variety of chemicals and two major types of

bonding.bonding. 2 Major 2 Major

types of types of bonding.bonding.

Covalent Covalent Bonding is Bonding is the sharing the sharing of electrons.of electrons.

Ionic Ionic bonding is bonding is the transfer the transfer of electrons.of electrons.

Covalent BondingCovalent Bonding Covalent bonding is Covalent bonding is

when atoms share when atoms share electrons to create a electrons to create a full valence shell.full valence shell. Hydrogen is unstable, Hydrogen is unstable,

it has 1 valence it has 1 valence electron in the 1electron in the 1stst energy level.energy level.

Oxygen is unstable Oxygen is unstable because it has six because it has six electrons in the 2electrons in the 2ndnd energy level.energy level.

When 2 hydrogen When 2 hydrogen combine with 1 combine with 1 oxygen all atoms have oxygen all atoms have full valence electrons full valence electrons by sharing the by sharing the electrons.electrons.

Examples of Covalent BondsExamples of Covalent Bonds

Chlorine GasChlorine Gas

GlucoseGlucose

ProteinProtein

Ionic Bonds – Transfer of Electrons to Ionic Bonds – Transfer of Electrons to Create Full Valance Energy Levels.Create Full Valance Energy Levels.

When an atom When an atom looses or gains an looses or gains an electrons we call electrons we call them an ion.them an ion. If you loose an If you loose an

electron, then you electron, then you become slightly become slightly positive.positive.

If you gain an If you gain an electron, then you electron, then you become slightly become slightly negative.negative.

Opposites attracts +/-Opposites attracts +/- You get an ionic bondYou get an ionic bond

Ionic Bonds are best represented by salts.Ionic Bonds are best represented by salts.

Sodium ChlorideSodium Chloride Potassium ChloridePotassium Chloride Magnesium ChlorideMagnesium Chloride

Exit PassExit Pass

What are valence electrons?What are valence electrons?

What does stability mean when we talk What does stability mean when we talk about bonding?about bonding?

What is the maximum electrons allowed What is the maximum electrons allowed on the 1on the 1stst, 2, 2ndnd, and 3, and 3rdrd energy levels? energy levels?

What is the difference between an ionic What is the difference between an ionic and a covalent bond?and a covalent bond?

Darth Monkey Street Says,Darth Monkey Street Says,

““Electrons are Electrons are responsible for all responsible for all chemical reactions. chemical reactions. If you get negative If you get negative with me I will react with me I will react with my light saber with my light saber on you!”on you!”