Chemical Bonding

Question 1

Describe the Bohr Model

Answer 1

• Focuses on the electrons
• Neutrons and Protons in nucleus
• electrons move at constant speed in fixed orbitals around the nucleus (planets around sun)

-involves energy levels

each electrons have specific amounts of energy
- if atom gains or loses NRG, the NRG of electrons can change

Question 2

Describe Energy Levels

Answer 2

• possible energies that electrons in atom can have are known as ENERGY LEVELS
  -areas at specific distances from the nucleus.
• 7 known.

-further electrons are from nucleus the more readily available they are for bonding.

• each electrons have specific amounts of energy
• if atom gains or loses NRG, the NRG of electrons can change

Question 3

How to energy levels work?

Answer 3

• think of steps on a staircase … can only move in whole step increments
  (no in between)
• lowest step = Ground State
• electrons move up and down when atom gain or loses NRG

Question 4

Evidence for Energy Levels

Answer 4

EMISSION SPECTRUM
- measure energy changes in an atom by the type of visible light given off by the object through ES.

Question 5

What is a continuous spectrume

Answer 5

Type of emission spectrum.

• objects at HIGH temperature emit continuous spectrums when viewed through defraction.
• no gaps.

Question 6

What is a line spectrum

Answer 6

Type of Emission Spectrum

• When a PURE sample is heated and emmited light passes through deffraction grating, few narrow lines are shown.

Question 7

How do line spectrums work?

Answer 7

Example of H atom

1. Electricity causes H atoms to gain NRG, exciting electrons causing them to move up energy levels.
2. H atom releases this NRG and returns to ground state by emitting certain wavelengths of visible light.

• these wavelenghts correspond to distinct colours which indicates the amount of NRG gained or lost.

Question 8

How do line spectrums emit different colours?

Answer 8

No two elements have the same set of energy levels. Different elements emit different colours of light.

Question 9

Describe the Electron Cloud Model.

Answer 9

• deals with PROBABILITY
• It is a visual model of the most likely locations for electrons in an atom.
• represents all orbitals in an atom
  is 3-D

Question 10

How are Atoms made up

Answer 10

Positively charged protons and neutral neutrons in a nucleus surrounded by negatively charged electrons that obit the nucleus.

Question 11

What are Ions

Answer 11

An atom that has gained or lost an electron, giving it an electrical charge.

• number or protons does not change.

Question 12

What is a Cation?

Answer 12

Positively charged ion caused by losing one or more electron.

Question 13

What is an Anion?

Answer 13

Negatively charged ion caused by gaining one or more electron.

Question 14

What is electron configuration?

Answer 14

Refers to how electrons are arranged around the nucleus.
- Determines the chemical behavior of every element.

Question 15

What is an ionic bond?

Answer 15

TRANSFER of valence electrons from a metal to a nonmetal to form an ionic compound.

Question 16

What is a covalent bond?

Answer 16

SHARING of valence electrons to create a stable octet.
- shared electrons are considered to belong to both.
-pairs that don’t participate are called lone electron pairs.

Question 17

What is polar covalent bonding?

Answer 17

Unequal sharing of electrons between atoms, meaning an electron spends more time near one atom than the other.

• creates a separation of charges called a dipole, resulting in a partial charge on each atom.