topic 1

Question 1

what is a compound

Answer 1

2 or more elements chemically bonded together in fixed proportions

Question 2

what is an elemenet

Answer 2

a substance made up of the same atom

Question 3

what is a molecule

Answer 3

any elements chemically bonded together even if theyre the same atom

Question 4

what is a mixture

Answer 4

2 or more elements not chemically bonded together

Question 5

what is the relative atomic mass and charge for electron proton and nuetron

Answer 5

electron- -1 charge and very small mass
nuetron- 0 charge and 1
proton- +1 charge and 1

Question 6

what is an isotope

Answer 6

different forms of the same element that have the same number of protons but different number of neutrons

Question 7

what is an ion

Answer 7

atoms with an overall charge due to the loss or gain of electrons

Question 8

what are the physical seperation techniques

Answer 8

crystallisation, simple distillation, fractional distillation, filttration, paper chromoatgaprhy

Question 9

when is filtartion used

Answer 9

used to seperate an insoluble solid from a liquid

Question 10

when is fractional and simple distillation used

Answer 10

fractional distillation-used when you want to seperate a mixture of liquids with different boiling points
simple distillation- when you want to seperate a solid from a liquid and keep the liquid at the same time

Question 11

when is crystallisation used

Answer 11

used to seperate a soluble solid from a liquid

Question 12

when is paper chromatography used

Answer 12

used to seperate substances based on different solubilties

Question 13

why do we draw the starting line in pencil

Answer 13

because if we drew it in pen then the ink would dissolve in the solvent and move up the paper

Question 14

what is the equation for relative atomic mass

Answer 14

                     100

Question 15

describe the alpha scattering experiment

Answer 15

ernest rutherford fired a beam of positively charged alpha paricles at a sheet of gold foil. some particles went through, some deflected back and some were scattered. this lead him to conclude that the mass is concentrated at the centre of the atom, the t=centre of the atom has a positive charge and that the atom is mostly empty space

Question 16

how is the nuclear model different to to the plum pudding model

Answer 16

the nucleus is a positive structure at the centre of the atom and theres electrons orbiting around it.

Question 17

describe the properties of group1 metals

Answer 17

the alkali metals are soft,very reactive and have low melting and boiling points. as you go down the group, the distance from the nucleus to the outermost electron shell increases, this weakens the electrostatic attraction between the 2 resulting in the outermost electron being lost more easily

Question 18

describe the properties of the group 0 elements

Answer 18

the noble gases are unreactive as they all have a full outer shell. they have low melting and boiling points. non flammable

Question 19

describe properties of group 7 elements

Answer 19

the halogens have a low melting and boiling point.
reactivity decreases as you go down.

Question 20

describe the properties of the transition elements

Answer 20

high melting, low reactivity,hard metals,useful as catalysts