Assessment C1 Revision

Question 1

Explain why electrons are shared

Answer 1

When an atom loses or gains electrons to form ions they’re trying to get a full outer shell which makes the atom very stable

Question 2

Which groups are most likely to form ions and why?

Answer 2

Group 1 and 2- are metals and they lose electrons to form positive ions (cations)
Group 6 and 7- are non metals they gain electrons to form negative ions
(anions)

Question 3

What is an ionic bond?

Answer 3

When a metal and non metal react they have oppositely charged ions which makes the strongly attracted by electrostatic forces. They have a structure called a giant ionic lattice and the ions form a closely packed regular lattice

Question 4

State the properties of ionic compounds

Answer 4

They have a high melting and boiling point because the bonds between the ions are very strong. It takes a lot of energy to overcome this reaction. When solid they can’t conduct electricity, and dissolve easily in water allowing them to conduct electricity

Question 5

What is a covalent bond?

Answer 5

Similar properties as an ionic bond, happens in compounds of non metals (H2O) and in non metal elements (CL2)

Question 6

What are molecular substances?

Answer 6

Made up of molecules containing a few atoms joined together by covalent bonds. A few examples are Hydrogen, Chlorine, Oxygen and Nitrogen. Most molecular substances are gases or liquids at room temperature, as the molecules get bigger the melting and boiling points increase.

Question 7

What is metallic bonding?

Answer 7

In metals the electrons in the outer shell are delocalised (free to move) they have electrostatic attraction between the positive metal ions and the shared negative electrons. They have a regular structure which is in rows

Question 8

How do you calculate the mass of an element?

Answer 8

A x number of atoms that element divided by Mr of the compound x 100

Question 9

What is Avogadro’s constant?

Answer 9

6.02 x 10 (23)

Question 10

What is the formula for moles?

Answer 10

Top: mass
left: number of moles
Right: Mr

Question 11

What is the formula of concentration.

Answer 11

Top: mass
Left: concentration
Right: volume

Question 12

What is a base?

Answer 12

A substance with a PH greater than 7

Question 13

What is the equation for neutralization?

Answer 13

Acid + base > salt + water
H+ + OH- > H2O

Question 14

What are acids?

Answer 14

They have a PH between 1 and 6, strong acids completely ionise in water, all the particles dissociate to release H+ ions. Weak acids don’t and only release some H+ ions

Question 15

What is the PH?

Answer 15

It’s the measure of the concentration of hydrogen ions

Question 16

What is the reaction of an acid?

Answer 16

All metal oxides and hydroxides react with acids to form a salt + water

Question 17

What is the reactivity series abbreviation method to learn?

Answer 17

Please Stop Lying Calling Me A Careless Zebra Instead Try Learning How Copper Saves Gold

Question 18

Which metals are extracted by electrolysis?

Answer 18

Metals higher than carbon

Question 19

What happens to the metals in a displacement reaction?

Answer 19

The metal ion gains electrons and the metal atom loses electrons

Question 20

What happens during electrolysis?

Answer 20

The positive ions go towards the cathode to gain electrons (reduction)
The negative ions go towards the anode to lose electrons (oxidation)

Question 21

What chemicals were released in the earths early atmosphere?

Answer 21

Carbon dioxide, methane and ammonia, volcanic activity also released nitrogen

Question 22

What is agriculture?

Answer 22

When more farm animals produce more methane through their digestive processes

Question 23

What is the charge of the nucleus?

Answer 23

Positive

Question 24

How do u know the number of electrons?

Answer 24

The number of protons equals the number of electrons

Question 25

Which one is the atomic and mass number?

Answer 25

Mass number on the top atomic on the bottom

Question 26

How do you get the number of neutrons?

Answer 26

Subtract the atomic number from the mass number

Question 27

What are isotopes?

Answer 27

Isotopes have the same atomic number but different mass numbers

Question 28

How do you calculate relative atomic mass?

Answer 28

Sum of (isotope abundance x isotope mass number) / sum of abundance of all the isotopes

Question 29

What is chromatography?

Answer 29

Separating dyes by writing it on a piece of paper and putting that paper in water so the water contaminates the sheet and separates the dyes

Question 30

What is evaporation?

Answer 30

A solution is poured into an evaporating dish, it’s heated so the solvents will evaporate and the solution gets more concentrated, eventually crystals will start to form,

Question 31

What is crystallization?

Answer 31

Pour the solution into an evaporating dish then heat the solution and some of the solvent will evaporate so the solution will get more concentrated. When the solution has evaporated or when crystals start to form, let the dish cool down, the salt should start to form crystals as it becomes insoluble in the cold, filter the crystals out and put them in a warm place (drying oven)

Question 32

What is the plum pudding model?

Answer 32

It shows the atom as a ball of positive charge with electrons stuck in it

Question 33

How do acids and bases neutralize each other?

Answer 33

Acid + base = salt + water
H+ + OH- = H2O

Aqueous