chemistry

Question 1

compound

Answer 1

a substance that has two or more elements chemically combined in a fixed ratio.

Question 2

mixture

Answer 2

substances that have two or more elements or compounds in a variable ratio

Question 3

element

Answer 3

a substance that can’t be broken down to anything simpler. made up of only one type of atom can be single or molecules

Question 4

properties of metals

Answer 4

shiny, high melting boiling points, solid at room temperature (mercury is liquid), malleable, ductile and good electrical and thermal conductors

Question 5

malleable

Answer 5

ability to be hammered into a shape

Question 6

ductility

Answer 6

ability to be stretched into a wire

Question 6

relative mass of protons, neutrons and electrons

Answer 6

proton 1
neutron 1
electron 1/1840

Question 7

charges of electron proton and neutron

Answer 7

proton +1
neutron 0
electron -1

Question 8

what did democritus find

Answer 8

discovered/ thought that atoms were indivisible particles

Question 9

what did john dalton find

Answer 9

atoms are solid balls and that compound have fixed ratios

Question 10

what did jj thompson find

Answer 10

found negatively charged electrons that are scattered throughout the atom - plum pudding model

Question 11

what did ernest rutherford find

Answer 11

when alpha particles (positive) were fired at gold foil lots were deflected meaning there was a positive charge in a small nucleus

Question 12

what did neil’s bohr find?

Answer 12

looked at atomic emmision spectra ( the light ammited by elements when heated) found electrons are in energy levels

Question 13

what did james chadwick discover?

Answer 13

found a neutral particle - the nucleus contains protons and neutrons

Question 14

what is an isotope?

Answer 14

are atoms of the same element which have different number of neutrons so a different mass number

Question 15

what is relative atomic mass? (simple)

Answer 15

the average mass of an atom

Question 16

formula for relative atomic mass?

Answer 16

Ar = ( relative isotope mass 1 x %) + (realtive isotope mass 2 x %)/100

Question 17

how many electrons on each shell?

Answer 17

2,8,8

Question 18

connection between group number and electron configuration?

Answer 18

the number on outer electron shell is the group number

Question 19

connection between period number and electron configuration?

Answer 19

period number equals the number of electron shells

Question 20

connection between metals and non metals and electron configuration

Answer 20

metals have less than four electrons in outer shell whilst no metals have 4 or more