T1 atomic structure and the periodic table

Question 1

what is an atom

Answer 1

smallest part of an element what can exist

Question 2

what is an element

Answer 2

substance of only one type of atom

Question 3

what 2 groups can elements be classified into

Answer 3

metals and non-metals

Question 4

what is a compound

Answer 4

two or more elements combined chemically in fixed proportions which can be represented by formulae

Question 5

do compounds have the same properties as their constituent elements

Answer 5

no, they have different properties

Question 6

what is a mixture?

does it have the same chemical properties as its constituent materials?

Answer 6

mixture consists of two or more elements or compounds not chemically combined together

does have the same chemical properties

Question 7

what are the methods through which mixtures can be separated

do these involve chemical reactions

Answer 7

filtration, crystallisation, simple distillation, fractional distillation, chromatography

don’t involve chemical reactions

Question 8

describe and explain simple distillation

Answer 8

used to separate liquid from a solution - the liquid boils off and condenses in the condenser

thermometer will read the boiling point of the pure liquid, get to keep the liquid

Question 9

describe and explain crystallisation

Answer 9

solution is heated and some of the solvent evaporates, leaving behind a saturated solution

saturated solution is allowed to cool and crystals to form

crystals can be separated by filtration

Question 10

describe and explain evaporation

Answer 10

technique for separation of a solid dissolved in a solvent from a solvent (eg salt from H2O)

solution is heated until all the solvent evaporates, the solids stays in the vessel

Question 11

describe and explain fractional distillation

Answer 11

technique for separation of a mixture of liquids, works when liquids have different boiling points

the fractionating column contains glass beads, helps to separate the compounds

industry - mixtures are repeatedly condensed and vapourised

column is hottest at bottom and coldest at top

liquids will condense at different heights

Question 12

describe and explain chromatography

Answer 12

place a piece of paper with a spot containing a mixture in a beaker with some solvent

bottom of paper has to be in contact with the solvent

solvent level will slowly start to rise, separating the spot into few spots

Question 13

what is a separating funnel

Answer 13

apparatus for separating immiscible liquids

two immiscible liquids of different densities will form two distinct layers in the separatory funnel

can run off the bottom layer (liquid with greater density) to a separate vessel

Question 14

describe the plum-pudding model

Answer 14

atom is a ball of positive charge with negative electron embedded in it

Question 15

describe the Bohr/nuclear model and how it came about

Answer 15

suggests that electrons orbit the nucleus at specific distances (shells) - came about from the alpha scattering experiments

Question 16

what did the work of James Chadwick provide evidence for

Answer 16

existence of neutrons in the nucleus

Question 17

relative masses and relative charges of the proton, neutron and electron

Answer 17

Masses: 1, 1, very small
charges: 1, 0, -1

Question 18

radius of an atom

Answer 18

0.1 nm

Question 19

radius of a nucleus and what is it compared to that of the atom

Answer 19

1x10-14 m and 1/10000

Question 20

name given to the number of protons in the nucleus

Answer 20

atomic number

Question 21

atoms of the same element have the same number of which particle

Answer 21

protons

Question 22

what is the mass number

Answer 22

total number of protons and neutrons

Question 23

equation for the number of neutrons using mass number and atomic number

Answer 23

subtract atomic number from the mass number

Question 24

what is an isotope

do isotopes of an element have the same chemical properties

Answer 24

atoms of the same element that have a different number of neutrons

have the same chemical properties as they have the same electron structure

Question 25

what is the relative atomic mass

Answer 25

average mass value which takes the mass and abundance of isotopes of an element into account, on a scale where mass of 12C is 12

Question 26

what are ions

Answer 26

charged particles formed when atoms lose (positive ions) electrons or gain (negative ions) electrons

Question 27

properties of metals

Answer 27

``` high boiling/melting point conducts heat and electricity shiny malleable high density basic oxides ```

Question 28

properties of non-metals

Answer 28

``` low boiling/melting point don't conduct heat or electricity - minus graphite dull brittle low density acidic oxides ```

Question 29

what is formed when a metal reacts with a non-metal

Answer 29

ionic compound (made of positive and negative ions)

Question 30

what is formed when a non-metal reacts with a non-metal

Answer 30

molecular compound containing covalently bonded atoms atoms share electrons, as opposed to transferring electrons between each other

Question 31

group 0 elements are known as

Answer 31

noble gases

Question 32

what makes the periodic table periodic

Answer 32

similar properties of elements occur at regular intervals

Question 33

elements in the same group have the same number of electrons in their outer shell; what does this tell us about their chemical properties

Answer 33

they have similar chemical properties

Question 34

early periodic tables were arranged by

Answer 34

increasing atomic mass

Question 35

knowledge of what made it possible to explain why the order based on atomic weights was not always correct

Answer 35

isotopes

Question 36

elements that react to form positive ions are

Answer 36

metals

Question 37

elements in group 1 are known as

Answer 37

alkali metals

Question 38

state three characteristics of the alkali metals

Answer 38

1 electron in outer shell low density are stored under oil to prevent reactions with oxygen or water soft, can be cut with a knife

Question 39

how do group 1 elements react with non-metals why are these reactions similar for the different group 1 elements

Answer 39

form ionic compounds which are soluble white solids which form colourless solutions all have 1 electron in outer shell

Question 40

how do group 1 elements react with water

Answer 40

release hydrogen and form hydroxides which dissolve to form alkaline solutions react vigorously with water fizzing and moving around on the surface of water

Question 41

how does reactivity change moving down group 1 why

Answer 41

increases as the atoms get larger and the distance between the nucleus and the outer electrons increases thus, the attraction from the nucleus decreases, allowing them to easily lose electrons

Question 42

state 5 characteristics of group 7

Answer 42

``` 7 electrons in outer shell coloured vapours diatomic molecules form ionic salts with metals form molecular compounds with non-metals ```

Question 43

state 5 group 7 elements and states of matter of molecules they form

Answer 43

F2 is a pale yellow gas Cl2 is a pale green gas Br2 is a dark brown liquid I2 is a grey solid

Question 44

state 3 changes that occur in group 7 as one moves down the group

Answer 44

higher relative molecular mass higher melting and boiling point less reactive - less easily gain electrons

Question 45

a more reactive halogen displaces a less reactive one from an aqueous solution of iits salt; explain the trend in reactivity of halogens in these reactions

Answer 45

reactivity decreases down the group as we go down the group, the atoms get larger, so an incoming electron will be less tightly held by the attractive forces from the nucleus

Question 46

compare group 1 metals and transition metals

Answer 46

G1 and transition metals are heat and electricity conductors, shiny when polished and form ionic compounds with non-metals transition metals have higher densities and higher melting points, less reactive and harder than group 1 metals

Question 47

state 3 common characteristics of transition metals

Answer 47

ions with different charges coloured compounds catalytic properties

Question 48

what is a catalyst

Answer 48

chemical substance that increases the rate of a chemical reaction not used up over the course of the reaction

Question 49

state the colours of flames observed when lithium, sodium and potassium burn in oxygen

Answer 49

crimson-red : Li yellow-orange: Na lilac: K

Question 50

describe the properties of noble gases discuss the trends in properties down the group

Answer 50

non-metals, gases, low boiling point, unreactive (full outer shell so don't easily accept or lose electrons) boiling point increases down the group, as atoms get heavier