1 - Energy, elements, atoms and bonding.

Question 1

What are the 2 types of energy?

Answer 1

kinetic and potential

Question 2

What is kinetic energy?

Answer 2

energy of movement

Question 3

What is potential energy?

Answer 3

energy of position

Question 4

metabolism

Answer 4

sum of all chemical reactions in the body

Question 5

Anabolism

Answer 5

making molecules for storage

Question 6

Catabolism

Answer 6

Metabolic pathways that break down molecules, releasing energy.

Question 7

Element

Answer 7

A substance that cannot be broken down into simpler substances

Question 8

How many naturally occurring elements are essential for life?

Answer 8

25/92

Question 9

which elements make up most of living matter; how much do they make up?

Answer 9

COHN - 96%

Question 10

which elements make up the remaining 4% of matter?

Answer 10

Phosphorus, Sulphur, Calcium, Potassium, Iron, Iodine

Question 11

What is an atom?

Answer 11

Smallest unit of matter which still retains the properties of an element.

Question 12

How many protons are there in 1g? What is this Known as?

Answer 12

6.022x10^23

This is known as avogadro’s constant

Question 13

Describe the charges on electrons and protons in relation to each other.

Answer 13

Equal and opposite

Number of protons = number of electrons

Question 14

Describe atomic orbitals.

Answer 14

• filled orbitals are more stable than unfilled
• elements will try to lose/gain electrons in order to obtain filled orbitals -> basis of reactivity
• valence electrons directly involved in chemical reactions will form bonds.

Question 15

Describe the shape of the first 3 orbitals

Answer 15

1s : spherical

2s: spherical but larger than 1s
2p: dumbbell shape

Question 16

What is a compound?

Answer 16

Substance consisting of 2 or more elements in a fixed ratio.

Question 17

What is covalent bonding?

Answer 17

Sharing of electrons by 2 atoms

Question 18

When does a non-polar covalent bond occur?

Answer 18

When there is an equal sharing of electrons

Question 19

When does a polar covalent bond occur?

Answer 19

when electrons are shared unequally

Question 20

Describe hydrogen bonding

Answer 20

• Only available with H, O and N
• Weak compared with covalent and ionic bonding
• Together the bonds become strong

Question 21

What is an ionic bond?

Answer 21

Bond formed when 2 atoms very different in attraction for valence electrons come together forming a crystal

Question 22

Describe Van der Waals forces

Answer 22

• interactions between electron clouds
• weak
• short range
• collectively strong