Metals and Non metals

Question 1

What is the difference between monatomic and diatomic elements?

Answer 1

• Monatomic consist of SINGLE uncombined atoms
  ie. the noble gases; no need to form bonds
• diatomic elements exists as 2 of same atoms bonded tog.
  eg. Hydrogen, Oxygen, Nitrogen (subscript 2)

Question 2

atomic number?

Answer 2

number of protons in nucleus

Question 3

mass number?

Answer 3

number of protons and neutrons in nucleus

Question 4

ion?

Answer 4

an atom/group of atoms that has gained or lost electron/s (has pos. or neg. charge)

Question 5

what is ionic bonding?

Answer 5

• metal + non metal
• transfer of electrons leaves pos ion and neg ion
• the pos. ion (metal) and neg. ion (non metal) attract and combine to form an ionic compound (continuous + - lattice)

Question 6

what properties differ metals from non metals

Answer 6

metals - shiny, malleable/ductile, good conductors of electricity, *SOLID at room temp. (except mercury)

non metals - dull, brittle, good insulators, *can be SOLID, LIQUID or GAS at room temp.

Question 7

what group are alkali metals, halogens and noble gases

Answer 7

Alkali = group I
Alkali earth metals = group II
Halogens = group VII
Noble gases = group VIII

Question 8

what does the period number and group number represent

Answer 8

period number = number of occupied shells

group number = number of valence electrons

Question 9

Why do noble gases exist as single atoms

Answer 9

they have a full outer shell and are stable, therefore do not need to donate/accept electrons (so are unreactive)

Question 10

What are the charges of simple ions

Answer 10

Group I = valance of 1+
Group II metals = valance of 2+
Group III metals = valance of 3+
(POSITIVE IONS)

Group VII non-metals = 1-
Group VIII non-metals = 2-
(NEGATIVE IONS)

Question 11

What is covalent bonding/how does it work?

Answer 11

when non-metal atoms SHARE electrons to become stable (have full outer electron shell)

• pairs of electrons are shared by atoms
• forms molecule

Question 12

What is a chemical reaction

Answer 12

• process involving successful collisions of particles to break chemical bonds + create new ones
• produces new substance and is hard to reverse

Question 13

what is the rate of reaction?

Answer 13

• a measure of the amount of reactants being converted into products per unit time

Question 14

what are examples of slow reactions + reactions favourable to be slow

Answer 14

• rusting
• chemical wearing of rocks
• decay of animals/plants

Favourable

• rusting
• spoiling of food

Question 15

Examples of fast reactions + favourable to be fast

Answer 15

• combustion
• explosions

Favourable

• digestion in body
• cooking food

Question 16

What are the 4 factors that can change a reaction

Answer 16

Temperature, surface area, concentration, catalysts

Question 17

How is the rate of reaction changed by altering temperature

Answer 17

• higher temp = particles moving faster and increasing number of collisions per unit time AND force of collisions
• increases chance of successful collisions, thus rate

Question 18

How is rate of reaction changed by altering surface area

Answer 18

• more surface area = more particles available for collisions per unit time
• increases chance of successful collisions, thus rate

Question 19

how is reaction rate affected by altering concentration

Answer 19

• increasing concentration = more particles per unit volume, increasing collisions per unit time
• increase chance of successful collisions, thus rate

Question 20

What is the effect of a catalyst on reaction rate

Answer 20

• speeds up reaction by lowering activation energy (provides alternate path)
• does not change frequency of actual collisions, only increases frequency of SUCCESSFUL collisions
• not changed, used up or consumed in reaction themselves

Question 21

What is a biological catalyst and why does our body rely on it

Answer 21

• Enzymes (proteins that speed up chemical reactions in cells)
• allows reactions within body to happen at sufficient rate at body temp. for survival

Question 22

what is the reactivity in relation to group/period

Answer 22

• decreases down a group

- increases across a period

Question 23

what substance can slow down reaction

Answer 23

inhibitor

Question 24

naming ions? - what is ammonium

Answer 24

NH₄⁺

Question 25

what are examples of catalysts?

Answer 25

nickel placed in explosions??

Question 26

what are examples of enzymes?

Answer 26

amylase in saliva speeds up breakdown of starch into glucose