P1- Topic 1-Atomic structure and the periodic table

Question 1

what is an element

Answer 1

an element is a substance of only type of a atom

Question 2

what is a compound

Answer 2

two or more elements combined chemically in fixed proprtions

Question 3

what is a mixture

Answer 3

two or more elements not chemically combined together

it has the same chemical properties

Question 4

what 5 ways mixtures can be separated

Answer 4

fractional distillation
chromotography
simple distillation
crystallisation
filtration

Question 5

describe and explain simple distillation 3

Answer 5

Simple distillation is used to separate liquid from a solution

solution heated, solution with lowest boiling point evaporates first.

the liquid boils off and condenses in the condenser.

vapour travels through the condenser and turns into a pure liquid.

Question 6

Describe and explain

crystallisation 7

Answer 6

Evaporation (e.g. salt from H2O).
used to separate a soluble solid from a solution

solution is heated until all the solvent evaporates; the solids stays in the evaporating dish

heated using a bunsen burner or water bath

cool down the solution.

the solid starts to crystallise,becomes concentrated

crystals collected and separated

from the solvent by filtration.

Question 7

Describe and explain

fractional distillation

Answer 7

Fractional distillation for the separation of a mixture of liquids with different boiling points

fractionating column placed on top of the heated flask.

lowest boiling point evaporates first.

condenses at the top of the column and can be collected

mixtures are repeatedly condensed and vapourised.

The column is hot at the bottom and cold at the top.
the liquids will condense at different heights of the column

Question 8

Describe and explain

filtration 4

Answer 8

to separate an insoluble solid from a liquid

insoluble solid gets caught in the filter paper,
because the particles are too big to fit through the holes in the paper.

The filtrate is the substance that comes through the filter paper.

Apparatus: filter paper + funnel.

Question 9

Describe and explain chromatography

Answer 9

used to separate a mixture of substances dissolved in a solvent.

pencil line drawn 1cm from bottom

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

The bottom of the paper has to be in contact with the solvent.

The solvent level will slowly start to rise, separating the spot(mixture) into few spots (components).

Question 10

Describe the plum-pudding model

1

Answer 10

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

Question 11

Describe the Bohr/nuclear model and how it came

about 2

Answer 11

The nuclear model suggests that electrons orbit the nucleus at specific
distances (shells) – it came about from the alpha scattering experiments

Question 12

Later experiments led to the discovery of
smaller, positive particles in the nucleus; what
are these particles called?

Answer 12

Protons

Question 13

why the new evidence from the scattering experiment led to a change in the atomic model
2

Answer 13

the positively charged alpha particles were being repelled and deflected

-by a tiny concentration of positive charge in the center of the atom (the nucleus).

Question 14

Difference between the plum pudding model and nuclear model of an atom

Answer 14

-in the nuclear model negative electrons are not embedded in it rather orbit the nucleus

Question 15

Describe the structure of an atom

Answer 15

The atom has a small central nucleus (made up of protons and neutrons)
around which there are electrons

Question 16

State the relative masses and relative charges

of the proton, neutron and electron

Answer 16

Masses: 1, 1, very small ; Charges: 1, 0 , -1 (respectively

Question 17

Explain why atoms are electrically neutral.

Answer 17

They have the same number of electrons and protons

Question 18

What is the radius of an atom?

Answer 18

0.1 nm 1*10-¹⁰

Question 19

What is the radius of a nucleus and what is it

compared to that of the atom?

Answer 19

1 x 10^-14 m and 1/10,000

Question 20

What is an isotope? Do isotopes of a certain
element have the same chemical properties?
2

Answer 20

Atoms of the same element (same proton number) that have a different
number of neutrons.

same chemical properties as they have the same electronic structure

Question 21

What are ions?

2

Answer 21

Ions are charged particles

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

Question 22

The columns of the periodic table are called?

Answer 22

Groups

Question 23

The rows of the periodic

table are called…?

Answer 23

Periods

Question 24

Are elements in the same group similar or

different?

Answer 24

They may have similar chemical properties, as they have the same number of outer shell electrons

Question 25

In terms of energy levels, what are the differences between elements of the same period?

Answer 25

They have the same number of energy levels

Question 26

What makes the periodic table periodic?

Answer 26

Similar properties of elements occur at regular intervals

Question 27

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

Answer 27

Isotopes

Question 28

Mendeleev overcame some problems with thetable by doing what? He also changed the order of some elements based on what?

Answer 28

Leaving gaps; atomic weights

Question 29

Elements that react to form positive ions are…?

Answer 29

Metals

Question 30

Elements that do not form | positive ions are…?

Answer 30

Non-metals

Question 31

properties of metals 6

Answer 31

``` high melting/bpoiling point conduct heat and electricity shiny malleable high density basic oxidises ```

Question 32

properties of non metals 6

Answer 32

``` Low melting/bpoiling point doesnot conduct heat dull brittle low density oxidises acidic ```

Question 33

what are group 0 elements called

Answer 33

noble gases

Question 34

why are group 0 (noble gases) unreactive

Answer 34

They are unreactive and do not easily form molecules, because they have a stable arrangement of electrons (full outer shell).

Question 35

Trend of Group 0 elements 1

Answer 35

Non-metals gases low boiling points unreactive (full outer shell) they don’t easily accept or lose electrons). boiling point increases down the group, as the atoms get heavier.

Question 36

Elements in Group 1 are known as…?

Answer 36

The alkali metals

Question 37

State 4 characteristics of the Alkali Metals

Answer 37

All have one electron in their outer shell have low density are stored under oil (to prevent reactions with oxygen or water) are soft (can be cut with a knife).

Question 38

How do Group 1 elements react with non-metals? Why are these reactions similar for the different Group 1 elements?

Answer 38

form ionic compounds(soluble white solids) form colourless solutions – they all have one electron in their outer shell.

Question 39

How do Group 1 elements | react with water?

Answer 39

react vigorously with water to create an alkaline solution and hydrogen Li- fizzes steadily Na- fizzes rapidly K-ignites sparks, lilac flame disappears quickly

Question 40

How do Group 1 elements | react with oxygen? 4

Answer 40

They all react with oxygen to create an oxide (white solid) Li- red flame Na- orange flame K- lilac flame

Question 41

How do Group 1 elements | react with chlorine? 3

Answer 41

They all react with chlorine to form a white precipitate Na- bright yelllow flame K-more vigorous with sodium

Question 42

what is the trend of group 1 metal 4

Answer 42

The reactivity of the elements increases going down the group outer electron is less attracted to the nucleus and easier to loose greater distance between positive nucleus and negative outer electron outer electron shielded from the nucleus by the internal energy levels

Question 43

State five characteristics of | Group 7

Answer 43

7 electrons in outer shell - Coloured vapours - Diatomic molecules - Form ionic salts with metals - Form molecular compounds with non-metals

Question 44

State five State Group 7 elements and states of matter of molecules they form

Answer 44

Fluorine pale yellow gas. Chlorine, pale green gas. Bromine, dark brown liquid Iodine, grey solid.

Question 45

State three changes that occur in Group 7 as one moves down the group

Answer 45

Higher relative molecular mass - Higher melting and boiling point - Less reactive – less easily gain electrons

Question 46

what happens when a reactive halogen and a less reactive halogen in an an aqueous solution of its salt

Answer 46

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt Chlorine + Potassium Bromide → Potassium Chloride + Bromine

Question 47

what happens with a halogen and a metal

Answer 47

form ionic compounds in which the halide ion carries a -1 | charge.

Question 48

what happens with a halogen and a non-metal

Answer 48

they react with nonmetals to form covalent compounds, where there is a shared pair of electrons

Question 49

Compare Group 1 metals and | transition metals 4

Answer 49

Group 1 metals 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 than Group 1 metals They are less reactive and harder than Group 1 metals

Question 50

State three common characteristics of transition metals

Answer 50

- Ions with different charges - Coloured compounds - Catalytic properties

Question 51

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

Answer 51

Li- crimson red Na- yellow orange K- lilac

Question 52

how to calculate the abundance of isotope

Answer 52

((isotope 1 mass x abundance) + (isotope 2 mass x abundance)) ÷ 100

Question 53

educ

Answer 53

periodic table

Question 54

Describe the properties of noble gases. Discuss the trends in properties down the group 2

Answer 54

Non-metals, gases, low boiling points, unreactive (full outer shell; they don’t easily accept or lose electrons). The boiling point increases down the group, as the atoms get heavier.