topic 1

Question 1

what is an element plus example

Answer 1

a substance made of atoms with the same atomic number
na

Question 2

what is a compound plus example

Answer 2

substances formed from 2 or more different elements chemically bonded together in fixed proportions.
co2

Question 3

what is a mixture plus example

Answer 3

2 or more substance not chemically bonded together
h2o

Question 4

what is the relative mass of protons, neutrons and electrons

Answer 4

protons- 1
neutrons-1
electrons-very small

Question 5

what is the charge of protons neutrons and electrons?

Answer 5

neutrons-0
electrons- (-1)
protons-(+1)

Question 6

what is the atomic number and mass number

Answer 6

the mass number(top number) is the number of protons and neutrons
the atomic number(bottom number) is the number of protons/electrons

Question 7

equation for relative atomic mass

Answer 7

                        100

Question 8

what is a molecule and give an example

Answer 8

2 or more atoms held together by chemical bonds
o2 is an example

Question 9

what are the seperation techniques

Answer 9

filtration
distillation
crystallisation
chromatography

Question 10

what is filtration used for

Answer 10

to seperate insoluble solids from a liquid

Question 11

what is crystallisation used for

Answer 11

to seperate a soluble solid from a liquid

Question 12

what is a solvent

Answer 12

a liquid in which substances can dissolve

Question 13

what is a solute

Answer 13

the substance which is dissolved in a liquid

Question 14

what did democritus propose

Answer 14

proposed atoms were small spheres

Question 15

what did john dalton do

Answer 15

prsented his atomic theory based on that atoms were solid spheres and that different spheres were made up of different elements

Question 16

what did jj thompson do

Answer 16

discovered electron
proposed plum pudding model which was a ball of positive charge with negative electrons embedded

Question 17

what did ernest rutherford do

Answer 17

proposed nuclear model based on gold foil experiment where he shot positively charged alpha particles at a thin sheet of gold foil. some were deflected and some scattered which led him to conclude that there was a nucleus.
-discovered nucleus

Question 18

what did niels bohr do

Answer 18

proposed electrons orbit nucleus in fixed shells located at set distances from nucleus

Question 19

what did james chadwick do

Answer 19

found neutron

Question 20

the difference between the plum pudding model of the atom
and the nuclear model of the atom.