Atomic Structure

Question 1

what is an atom?

Answer 1

smallest part of an element that can exist, they make up everything

Question 2

what is an atom made up of?

Answer 2

proton - +1, 1 mu
neutron - 0, 1 mu
electron - -1, 1/2000 mu

Question 3

how are subatomic particles distributed?

Answer 3

neutrons and protons are stored in the nucleus which is positive and contains most of the atom’s mass
electrons orbit the nucleus in fixed positions in shells, following the 2.8.8 rule

Question 4

what is an element?

Answer 4

a substance made up of one type of atom

Question 5

what is a compound?

Answer 5

a substance made up of two or more different elements chemically combined

Question 6

what is a mixture?

Answer 6

a substance that contains tow or more elements and/or compounds that aren’t chemically combined

Question 7

how can you separate mixtures?

Answer 7

chromatography
filtration
crystallisation
distillation
fractional distillation

Question 8

when is chromatography used?

Answer 8

to separate a mixture of liquids (inks) using a stationary phase

Question 9

when is filtration used?

Answer 9

to separate insoluble solids from liquids

Question 10

when is crystallisation used?

Answer 10

to separate a mixture of a dissolved solid from a liquid with heat

Question 11

when is distillation used?

Answer 11

to separate two liquids with different boiling points using heat and condensation

Question 12

when is fractional distillation used?

Answer 12

to separate a mixture of liquids with different boiling points using heat, condensation and fractionating tower

Question 13

what is the atomic mass of an atom?

Answer 13

the number above the chemical symbol + the sum of protons and neutrons in an atom

Question 14

what is the atomic number if an atom?

Answer 14

the number under the chemical symbol + the number of protons/electrons in an atom

Question 15

how do you find the number of neutrons in an atom?

Answer 15

atomic mass - atomic number

Question 16

what is an isotope?

Answer 16

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

Question 17

what is relative atomic mass (RAM)?

Answer 17

the average mass of all the different isotopes of an atom

Question 18

RAM equation

Answer 18

(atomic mass x percentage)+(atomic mass x percentage)/100

Question 19

what is an ion?

Answer 19

a charged atom
cation - positive
anion - negative

Question 20

development of atom model

Answer 20

19th century - John Dalton = atoms = solid spheres + different spheres = different elements
1897 - J J Thompson = plum pudding model = ball of positive charge with electrons embedded in it
1909 - Ernest Rutherford = alpha particle scattering experiment = positively charged alpha particles fired at thin sheet of gold = most passed through atom + some were deflected + others deflected backwards = plum pudding wrong = mass concentrated in positive nucleus + cloud of negative electrons + atom is empty space
Niels Bohr = electrons orbit in fixed shells + discovered protons
James Chadwick = neutrons

Question 21

how are elements arranged in the periodic table?

Answer 21

by their properties (physical and chemical)
atomic mass
metals = right non metals= left
rows = periods = no. of shells
columns = groups = elements with similar properties

Question 22

how did Dmitri Mendeleev change the periodic?

Answer 22

1869 - rearranged periodic table and left gaps
elements were mainly arranged in order of atomic mass but some were switched due to their properties
gaps = elements with similar properties in same group + existence of undiscovered elements

Question 23

how are metals and non-metals different?

Answer 23

metals
- strong
- malleable
- conductors
- high melting/boiling points
- lustrous
non-metals
- dull
- brittle
- usually not solids at room temp
- aren’t really conductors
- lower density

Question 24

group 0 (noble gases) properties

Answer 24

• full outershell = inert/unreactive
• monatomic
• colourless gases at room temp
• non-flammable
• boiling/melting points
  increases as you go down the
  group
• low melting/boiling points
• glow brightly when high voltage
  electricity pass through them
  eg. neon lights

Question 25

group 1 ( alkali metals) properties

Answer 25

• very reactive
• soft
• low density
• reactivity increases + lower
  melting/boiling points as you
  go down the group
  reaction with water
• react vigorously = hydrogen
  gas released + metal hydroxide
  produced
  reaction with chlorine
• react vigorously = white metal
  chloride salts produced
  reaction with oxygen
• metal oxide formed

Question 26

group 7 (halogens) properties

Answer 26

• coloured vapours
• diatomic
• less reactive +higher
  melting/boiling points as you
  go down the group

Question 27

transition metal properties

Answer 27

• conductors
• very dense
• strong
• shiny
• form more than ion = colourful
  eg. copper sulfate
• good catalysts = iron for Haber
  process = ammonia

Question 28

transition metals vs alkali metals - 6 marker example 6/6

Answer 28

transition metals are strong, shiny and good conductors similar to ‘proper’ metals. transition metals can form multiple ions whereas alkali metals can only form a positive ion. transition metals have much higher points than group 1 metals. alkali metals are soft and some such as potassium can float on water however transition metals like nickel are much harder and sink in water. transition metals don’t react as vigorously with water, oxygen and group 7 elements for example, sodium reacts vigorously with water and produces a flame but manganese doesn’t react with water at room temp