Chapter 4- The chemistry of life (2)

Question 1

Are compounds heterogenous or homogenous?

Answer 1

Homogenous

Question 2

What is a heterogeneous mixture?

Answer 2

A mixture that contains a substance in different phases, e.g, ice with water

Question 3

What is a homogenous mixture?

Answer 3

A mixture that contains a substance in just one phase, e.g, just water

Question 4

What are the 3 types of chemical bonds?

Answer 4

1- Ionic
2- Covalent
3- Hydrogen

Question 5

How do electrons orbit?

Answer 5

In electron shells

Question 6

What does each electron shell represent?

Answer 6

It represents a different energy level

Question 7

In terms of potential energy, what happens to the potential energy as electrons go further away from the nucleus?

Answer 7

The further away from the nucleus, the more potential energy they have.

Question 8

What is the valence shell?

Answer 8

Electrons in the outermost energy level that take part in chemical bonding

Question 9

What happens when the outermost shell is full?

Answer 9

It is chemically inert- a chemical substance that is unreactive.

Question 10

What elements are inert?

Answer 10

Noble gases

Question 11

How do atoms with less than 8 electrons in their valence shell get a full outer shell?

Answer 11

Gain, lose or share electrons.

Question 12

What ways can an atom have a full outer shell?

Answer 12

1- Ionic bonds
2- Covalent bonds
3- Hydrogen bonds

Question 13

What is an ionic bond?

Answer 13

When two oppositely charged ions attract

Question 14

How are electrons transferred?

Answer 14

Electrons can be donated from one atom to another.

Question 15

Does an electron donor become positively charged or negatively charged?

Answer 15

Positively charged (cation)

Question 16

Does an electron acceptor become positively or negatively charged?

Answer 16

Negatively charged (anion)

Question 17

What happens as a result, when the two atoms have opposite charges (ionic bonding)?

Answer 17

The charges will attract and will chemically bond.

Question 18

What is a covalent bond?

Answer 18

Where electrons are shared between two atoms.

Question 19

What does a covalent bond allow?

Answer 19

It allows both atoms to stabilise.

Question 20

What is the strongest bond and why?

Answer 20

Covalent bond because they are sharing an electron which neither atom wants to give up, so this ensures that the atoms remain strongly bonded to each other.

Question 21

What types of bonds can covalent bonds be?

Answer 21

Single, double, and triple bonds.

Question 22

In relation to chemistry, what are non-polar molecules?

Answer 22

Electrons that are shared equally between both atoms.

Question 23

In relation to chemistry, what are polar molecules?

Answer 23

Molecules that don’t always allow equal share of an electron.