C1 Atomic Structure/ Periodic Table

Question 1

state the product made from the reaction: METAL + NON-METAL + OXYGEN

Answer 1

METAL NON-METAL(-ate)

Question 2

describe the difference between simple and fractional distillation

Answer 2

• simple - used to obtain the solvent from a solution (water from salt) or two liquids with different boiling points (water from ethanol)
• fractional - used to separate one liquid from a complex mixture with diff boiling points (fractions in crude oil)

Question 3

describe distillation

Answer 3

• mixture is heated until the substance with the lowest boiling point boils+ turns into a gas
• gas enters the condenser+ condenses into a liquid, pure substance enters the beaker
• (fractional): fractionating column stops other substances from being extracted - will condense before reaching the condenser+ run back down into the flask

Question 4

name processes to separate mixtures (5)

Answer 4

• filtration (insoluble solids from liquids, sand from water)
• evaporation+ crystallisation (salt from a solution)
• chromatography (different coloured dyes in ink)
• simple distillation (water from salt, water from ethanol)
• fractional distillation (fractions in crude oil)

Question 5

why does the mass of the products sometimes appear to decrease or increase

Answer 5

• mass decrease - a gas is formed which escapes the container/ system into the surroundings
• mass increase - atoms from a gas in the atmosphere have been added

Question 6

describe Dalton’s atomic model

Answer 6

atoms are tiny, solid, indivisible spheres

Question 7

describe Thompson’s atomic model

Answer 7

plum pudding - a ball of positive charge with negative electrons in it

Question 8

describe Rutherford’s atomic model

Answer 8

nuclear model - a nucleus with positive charge, electrons that orbit, empty space in between (from alpha particle scattering experiment)

Question 9

describe Bohr’s atomic model

Answer 9

planetary model - electrons orbit in shells at fixed distances/fixed energy levels from the nucleus, empty space between

Question 10

describe Chadwick’s atomic model

Answer 10

atomic model- nucleus contains positive protons and neutrons with no charge, electrons orbit nucleus at fixed distances, empty space between (discovered neutrons)

Question 11

state the order of scientists+ their atomic models

Answer 11

DON’T Dalton - ball
TRY TO Thompson - plum pudding - electrons
REMEMBER Rutherford - nuclear -protons in nucleus
BRILLIANT Bohr - planetary - electrons orbit in shells
CHEMISTS - atomic - neutrons in nucleus

Question 12

describe an atom

Answer 12

• nucleus containing protons+ neutrons - almost all the atom’s mass is concentrated here
• electrons orbit in shells at fixed distances from the nucleus
• no overall electric charge/ neutral - contain an equal no. protons+ electrons

Question 13

describe the history of the Periodic table

Answer 13

• created by Mendeleev in 1869
• elements were placed in order of atomic weight and grouped according to chemical properties
  -> modern periodic table is ordered by atomic number: more accurate as atomic weight varies in isotopes
• he predicted the existence of undiscovered elements+ left gaps in the table

Question 14

describe properties of group 0 elements and reactivity

Answer 14

noble gases: helium, neon, argon, xenon
* full outer shells so don’t need to gain/lose electrons - therefore unreactive and exist as single atoms
* boiling points increase down the group
* low boiling points - gases at room temp
* colourless/odourless

Question 15

describe properties of group 1 elements

Answer 15

alkali metals: lithium, sodium, potassium, rubidium
* one electron in outer shell
* they react with oxygen (to form oxides), chlorine (to form chlorides), water (to form hydroxides)
* lower densities (than most metals)
* lower boiling points
* form compounds that are soluble white solids
* form positive ions with +1 charge
* soft+ malleable
* often stored in oil to stop them reacting with oxygen+ water vapour in air

Question 16

describe why reactivity increases down group 1 (alkali metals)

Answer 16

• need to lose one electron to form full outer shell
• as you go down the group the elements have more shells:
  increased distance between nucleus+outer electron so decreases electrostatic attraction between electron+nucleus protons;
  increased shielding effect - more inner electrons shield outer electron from electrostatic force
• therefore less electrostatic force = outer electron is more easily lost = reactivity increases down the group
• therefore boiling points decrease down the group

Question 17

describe properties and actions of group 7 elements

Answer 17

halogens: fluorine, chlorine, bromine, iodine
* need to gain one electron to form full outer shell
* low boiling points
* form compounds that are soluble white solids
* form negative ions with -1 charge
* coloured
* toxic
* higher molecular masses as you move down group
* react with metals to form the ionic compound halide salt
* a more reactive halogen can displace a less reactive halogen from a salt solution

Question 18

describe why reactivity decreases down group 7 (halogens)

Answer 18

halogens: fluorine, chlorine, bromine
* need to gain one electron to form full outer shell
* as you go down the group the elements have more shells:
increased distance between nucleus+outer shell so decreases electrostatic attraction between electron+nucleus protons;
increased shielding effect - more inner electrons shield outer electron from electrostatic force
* therefore less electrostatic force = outer electron is harder to gain = reactivity decreases down the group
* therefore boiling points increase down the group

Question 19

state properties of metals (8)

Answer 19

• good conductors of heat+electricity
• high density
• malleable (hammered into shape)
• ductile (drawn into wires)
• high melting+boiling points (except mercury)
• react w non-metals forming positive ions
• do not react with other metals
• form basic oxides

Question 20

state properties of non-metals (8)

Answer 20

• poor conductors of heat+electricity (except graphite)
• low density
• brittle (when solid)
• not ductile
• low melting+boiling points
• react w metals forming negative ions
• react w other non-metals forming molecules or compounds
• form acidic oxides