Compounds And Chemical Bonds

Question 1

Why do some atoms bind to one another ?

Answer 1

To lower the energy of the valence electrons
-increased stability
-core electrons are unaffected by bonding
-most stable atoms have full valance shells
-noble gases,at end of each period -unreative

Question 2

Define ionisation energy ?

Answer 2

Ionisation energy of an atom is the amount of energy required to remove an electron from an isolated atom into vacuum.
-Typically measured in kJ mol -1
- 1st IE = energy required to remove one valence electron

Question 3

Ionisation energy across a group ?

Answer 3

Increases

Question 4

1ST IE ?

Answer 4

?

Question 5

Electronegativity ?

Answer 5

An atoms attraction for electrons in a bond
-smaller atoms have a greater attraction for their valence electrons

Question 6

Electronegativity across ?

Answer 6

A group increases

Question 7

Pauling Electronegativity ?

Answer 7

? Add

Question 8

What is the key to chemical bonding ?

Answer 8

When atoms come together ,their electronegativities determine how they bond
Check online PowerPoint

Question 9

The triangle of something ?

Answer 9

Insert picture

Question 10

Ionic bonding ?

Answer 10

• Typically between metals and non metals
  -main group ions (s & p block) have full valence shells
  -Ions don’t exist in isolation
  
  • ionic compounds are electrically neutral
  • the charges on ions cancel out

Question 11

Examples of ionic compounds?

Answer 11

• Pure ionic compounds are usually solid at room temp and pressure
• main group ionic compounds are usually white
• dissolve in water to release ions
  E.g:

Question 12

What do pure ionic compounds contain ?

Answer 12

Extended lattice of ions
Which are held together by electromagnetic interactions
(Electrostatic or Colombic interactions)

Question 13

What is pure covalent bonding ?

Answer 13

Pair of shared electrons
(Bonding electrons spend most of their time between the 2 nuclei)
-covalent bonding is also electrostatic
Eg) Lewis dot diagram
Such as dehydrogenate

Question 14

Lewis structures for period 2,3

Answer 14

Have lone pairs or non bonding pairs
Most period 2 elements obey the octet rules(forming stable compounds (8))
However higher periods often disobey
-because bigger atomic sizing as group decreases -more space
-Period 3 - S,P,D -available all time in 3 shell

Question 15

Calculating & why formal charge ?

Answer 15

Helps us to to check Lewis structures by assigning electrons to atoms

FC = number of valence electrons in isolated atom-(non bonding valence electrons + 1/2 bonding electrons)

Most of the time all FCs in a neutral molecule are zero

Question 16

What is valency of a non-metal ?

Answer 16

The number of covalent bonds it may form while having FC=0

Eg)