y9 end of year chemistry revision

Question 1

why do atoms have no overall charge

Answer 1

an atom has equal numbers of protons(+1) and electrons(-1) so the charges cancel eachother out

Question 2

why do elements in the same group react in the same way

Answer 2

they have the same number of electrons in their outer shells

Question 3

what does the group number tell us

Answer 3

the number of electrons in the outermost shell

Question 4

what are rows in the periodic table called

Answer 4

periods

Question 5

what are columns on the periodic table called

Answer 5

groups

Question 6

why is helium in the same group as neon

Answer 6

both have full outer shells of electrons

Question 7

what are the elements in group 0 called

Answer 7

noble gases

Question 8

why are the elements in group 0 unreactive

Answer 8

all the elements contain a full outer shell of electrons
the atoms have a stable arrangement of electrons

Question 9

what happens to the size of atoms as you go down the group

Answer 9

get bigger

Question 10

what does the atomic number (proton number) show, and what is that always equal to

Answer 10

the number of protons in an atom
this is always equal to the number of electrons

Question 11

what does the relative atomic mass represent in the nucleus of an atom

Answer 11

protons and neutron sin the atom

Question 12

how many protons neutrons and electrons are in
23
Na
11

Answer 12

p=11
e=11
n=12

Question 13

give max number of electrons in the first four shells

Answer 13

shell 1 = 2
shell 2 = 8
shell 3 = 8
shell 4 = 18

Question 14

which energy level do electrons occupy first

Answer 14

the lowest energy level

Question 15

what is the electron structure of
23
Na
11

Answer 15

2,8,1

Question 16

what is a molecule

Answer 16

a compound formed from only non-metals

Question 17

what is an isotope

Answer 17

atoms of the same element with the same number of protons, but with a different number of neutrons

Question 18

why do atoms bond

Answer 18

to gain full outer shells of electrons

Question 19

which atoms are involved in ionic bonding

Answer 19

metal atoms and non-metal atoms

Question 20

in term of electrons, what happens during ionic bonding

Answer 20

atoms either lose or gain electrons

Question 21

define an ion

Answer 21

an atom with a charge that has lost or gained electrons

Question 22

which atoms form positive ions

Answer 22

metal atoms

Question 23

which atoms form negative ions

Answer 23

non-metal atoms

Question 24

what is the ionic formula of magnesium chloride

Answer 24

Mg and Cl makes MgCl2

Question 25

how did john dalton arrange the elements in the periodic table

Answer 25

in order of atomic mass

Question 26

how did john newlands arrange the elements in the periodic table

Answer 26

in order of atomic mass

Question 27

what law did john newlands use

Answer 27

the law of octaves

Question 28

what is the law of octaves

Answer 28

the law of octaves is that the properties of every eighth element seemed similar

Question 29

why did some scientists not agree with john newlands version of the periodic table

Answer 29

newlands law of octaves broke down after the twentieth element

Question 30

explain why the the discovery of gallium led to scientists adopting mendeleevs periodic table

Answer 30

when gallium was discovered, the properties were correct gallium fitted into one of the spaces in the periodic table

Question 31

how is the modern periodic table arranged

Answer 31

in order of atomic (proton) number

Question 32

what did john dalton suggest substances were made up of

Answer 32

atoms

Question 33

what did john dalton suggest atoms were like

Answer 33

tiny, hard spheres that could not be divided

Question 34

who discovered the electron

Answer 34

JJ.Thompson

Question 35

in the plum pudding model, what charge was the mass

Answer 35

positive

Question 36

what were embedded within the mass

Answer 36

electrons

Question 37

what overall charge did the atoms have

Answer 37

no overall charge

Question 37

in geiger and marsdens alpha scattering experiment, what charge did the alpha particles have

Answer 37

positive

Question 38

what were the alpha particles fired at

Answer 38

gold atoms

Question 39

what did all this evidence prove was in the atom

Answer 39

this was evidence in the nucleus of an atom

Question 40

according to rutherfords nuclear model of the atom, what does a nuclear atom contain

Answer 40

a dense positively charged nucleus suurounded by negatively charged electrons

Question 41

what did james chadwick's experimental work prove the existence of

Answer 41

neutrons in the nucleus

Question 42

why were new models of the atom adapted over time

Answer 42

new evidence was being found the new evidence didnt match the old model resulting in a new model being produced

Question 43

give the order in which sub-atomic particles were being produced - oldest 1st

Answer 43

electrons, protons and neutrons

Question 44

list three things you would observe when sodium is added to water

Answer 44

it would fizz it would move on the surface of the water it would float on the surface of the water

Question 45

name the gas produced when sodium is added to water

Answer 45

hydrogen

Question 46

write a word equation for the reaction between sodium and water

Answer 46

sodium + water -- sodium hydroxide + hydrogen

Question 47

write a balanced symbol equation for the reaction between sodium and water

Answer 47

2Na + 2H2O -- 2NaOH + H2

Question 48

why must alkali metals be stored in oil

Answer 48

to prevent them from reacting with oxygen/ water in the air

Question 49

how does the melting and boiling point of alkali metals change as you go down the group

Answer 49

the decrease

Question 50

describe the reaction between sodium and chlorine gas

Answer 50

sodium reacts vigorously with chlorine

Question 51

describe the the products of the reaction between sodium and chlorine

Answer 51

it produces sodium chloride, which is a white solid

Question 52

write a word equation for the reaction between sodium and chlorine

Answer 52

sodium + chlorine -- sodium chloride

Question 53

where on the periodic table are the transition metals

Answer 53

in the central block

Question 54

which atoms are involved in covalent bonding

Answer 54

non- metal atoms only

Question 55

what is a covalent bond

Answer 55

a shared pair of electrons

Question 56

which group is also known as the halogens

Answer 56

group 7

Question 57

describe how the melting point and boiling point of group 7 elements change as you go down the group

Answer 57

going down group 7 the melting and boiling points increase

Question 58

what method is used to separate a solid and liquid

Answer 58

filtration

Question 59

what is chromatography used for

Answer 59

to separate a mixture of dyes

Question 60

what is the stationary phase in chromatography

Answer 60

the paper

Question 61

what is the mobile phase in chromatography

Answer 61

the solvent which carries the substances

Question 62

name a common mobile phase

Answer 62

water

Question 63

what do you draw the line on the chromatography paper with? and why?

Answer 63

pencil, so it does not run, ink would run

Question 64

what does solubility mean

Answer 64

ability to be dissolved

Question 65

how can you identify which is the most soluble substance using a chromatogram

Answer 65

the substance which travels the furthest up the chromatography paper, is the most soluble ink

Question 66

what variables should be controlled when analysing substances using chromatography

Answer 66

use the same solvent ensure the solvent is at the same temperature

Question 67

why is a lid placed on the container in chromatography

Answer 67

to prevent the solvent from evaporating

Question 68

what name is given to the method used to separate a mixture of liquids(with different boiling points)

Answer 68

distillation