atomic structure and the periodic table

Question 1

what is a pure substance

Answer 1

consists of only one element or compound

Question 2

who published the first ideas about atoms in 1803

Answer 2

John Dalton, tiny spheres that couldn’t be divided

Question 3

who discovered the electron

Answer 3

JJ Thompson, led him to suggesting the plum pudding model of the atom, ball of positive charge with negative electrons embedded

Question 4

who did the gold foil experiment in 1909

Answer 4

Ernest Rutherford

Question 5

what conclusions did he make from the gold foil experiment

Answer 5

most passing straight through - mostly empty space
change direction - positive centre
reflecting - mass of atom concentrated in centre

Question 6

who proved that electrons orbited in shells

Answer 6

Niels Bohr

Question 7

who discovered neutrons in 1932

Answer 7

James Chadwick

Question 8

what proportion of a nucleus is the atom

Answer 8

1/10.000

Question 9

do isotopes of the same element have identical chemical properties

Answer 9

yes

Question 10

when did mendeleev publish his first periodic table

Answer 10

1869

Question 11

how did mendeleev arrange the first periodic table

Answer 11

• in order of increasing weight taking into account properties of elements and compounds
• this meant his table had gaps
• elements with similar properties lined up in groups

Question 12

what happened as a result of mendeleev leaving gaps

Answer 12

he predicted properties of future elements that turned out to be true

Question 13

what is an explanation for mendeleev pair resversals

Answer 13

different isotopes of elements existed, elements with higher relative atomic mass had lower atomic numbers

Question 14

do metals lose or gain electrons

Answer 14

lose electrons

Question 15

what is the difference between metal and non-metal oxides

Answer 15

metal oxides are basic

non-metal oxides are acidic

Question 16

what does malleable mean

Answer 16

means it can be hammered into shape without breaking

Question 17

what does ductile mean

Answer 17

means it can be made into a wire

Question 18

what is group 0

Answer 18

noble gases - on the far right of the periodic table

Question 19

why do noble gases increase in boiling points

Answer 19

• atoms become larger
• intermolecular forces between atoms are stronger
• more energy needed to overcome these forces

Question 20

what does inert mean for noble gases

Answer 20

extremely unreactive

Question 21

why are noble gases unreactive

Answer 21

they already have a full outer shell so don’t need to lose gain or share electrons

Question 22

what is group 1

Answer 22

alkali metals - on the far left of the periodic table

Question 23

physical properties of alkali metals

Answer 23

• soft
• low melting points
• low densities

Question 24

what happens to melting points for alkali metals

Answer 24

decrease

Question 25

what happens when alkali metals react with water

Answer 25

produce a metal hydroxide + hydrogen

Question 26

what do alkali metals melt to form in water

Answer 26

a ball

Question 27

what happens when alkali metals react with oxygen

Answer 27

produce metal oxides as white smoke

Question 28

what happens when alkali metals react with chlorine

Answer 28

form white solid chlorides that dissolve in water to form colourless solution

Question 29

why do alkali metals get more reactive

Answer 29

- atoms become larger - outer electron further from nucleus - force of attraction between nucleus and outer electron decreases - outer electron lost more easily

Question 30

what is group 7

Answer 30

halogens on the second to right hand side of periodic table

Question 31

how do halogens exist

Answer 31

a pair of halogen atoms joined by a single covalent bond

Question 32

what happens to melting and boiling points in halogens

Answer 32

increase as you go down because - molecules become larger - intermolecular forces become stronger - more energy needed to overcome these forces

Question 33

what happens when a halogen reacts with metals

Answer 33

produces salts held together by ionic bonds

Question 34

what happens to reactivity as you go down halogens

Answer 34

decreases

Question 35

what happens when a halogen reacts with hydrogen

Answer 35

hydrogen halide is formed gas at room temperature which dissolve in water to produce acidic solutions

Question 36

reactivity series

Answer 36

``` potassium sodium calcium magnesium aluminium carbon zinc iron tin lead hydrogen copper silver gold platinum ```

Question 37

properties unique to transition metals

Answer 37

- higher melting points - higher densities - greater strength - greater hardness

Question 38

what coloured compounds do the different metals form

Answer 38

not transition - white compounds | transition - coloured compounds

Question 39

what is a catalyst

Answer 39

substance that increases rate of reaction without being used up