FLASH - GCSE Chemistry 5.1.2 - The Periodic Table

Question 1

What are ions?

Answer 1

Ions are charged particles. They are formed when atoms lose electrons (positive ions) or gain (negative ions) electrons.

E.g. sodium positive ion, Na⁺, has an electronic configuration of 2,8 (same as Ne). An atom of sodium has lost one electron

Question 2

Compare the properties of
metals and non-metals

Answer 2

Question 3

What is formed when a
metal reacts with a
non-metal?

Answer 3

An ionic compound (made of positive and negative ions)

Question 4

What is formed when a
non-metal reacts with a
non-metal?

Answer 4

A molecular compound containing covalently bonded atoms.

Atoms share electrons, as opposed to transferring electrons between each other (cf. ionic compounds).

Question 5

Explain the following: solute, solvent, solution, miscible,
immiscible, soluble, insoluble.

Answer 5

A solute is a substance that is dissolved in a solvent. Together, they form a solution.

Miscible refers to the substances (particularly liquids) that mix together, e.g. water and alcohol. Water and oil are immiscible, i.e. they do not mix.

Soluble refers to the substance that can be dissolved in a solvent, e.g. salt in water. Insoluble substance won’t dissolve in a particular solvent.

Question 6

The columns of the periodic
table are called…?

Answer 6

Groups

Question 7

The rows of the periodic
table are called…?

Answer 7

Periods

Question 8

Are elements in the same
group similar or different?

Answer 8

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

Question 9

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

Answer 9

They have the same number of energy levels

Question 10

Electrons occupy particular energy
levels, with each electron in an atom at a
particular energy level; which available
energy level do electrons occupy?

Answer 10

The lowest available energy level

Question 11

The elements of Group 0
are more commonly known
as…?

Answer 11

The noble gases

Question 12

What makes the periodic
table periodic?

Answer 12

Similar properties of elements occur at regular intervals

Question 13

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 13

They have similar chemical properties

Question 14

In terms of shells, what is the
difference between elements
in the same period?

Answer 14

They have the same number of shells

Question 15

What change in shell
number is seen as one
moves down a group?

Answer 15

The number of shells increases

Question 16

Early periodic tables were
incomplete and elements were
placed in inappropriate groups if
what was to be followed?

Answer 16

The strict order of atomic weights

Question 17

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

Answer 17

Isotopes

Question 18

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

Answer 18

Leaving gaps; atomic weights

Question 19

The majority of elements
are…?

Answer 19

Metals

Question 20

Elements that react to form
positive ions are…?

Answer 20

Metals

Question 21

Elements that do not form
positive ions are…?

Answer 21

Non-metals

Question 22

Elements in Group 1 are
known as…?

Answer 22

The alkali metals

Question 23

State three characteristics of
the Alkali Metals

Answer 23

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 knife)

Question 24

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

Answer 24

They form ionic compounds which are soluble white solids which form colourless solutions – they all have one electron in their outer shell.

Question 25

How do Group 1 elements react with water?

Answer 25

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

Question 26

How does the reactivity change moving down Group 1? Why?

Answer 26

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

Question 27

State five characteristics of Group 7

Answer 27

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

Question 28

State Group 7 elements and their states of matter

Answer 28

---- Fluorine, F. F₂ is a pale yellow gas. Chlorine, Cl. Cl₂ is a pale green gas. Bromine, Br. Br₂ is dark brown liquid Iodine, I. I₂ is a grey solid

Question 29

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

Answer 29

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

Question 30

A more reactive halogen displaces a less reactive one from an aqueous solution of its salt; write the equations and state the colour change seen when chlorine reacts with sodium bromide and when chlorine/bromine reacts with sodium iodide.

Answer 30

Question 31

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

Answer 31

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. That’s why Cl₂ displaces Br^– and I^–.

Question 32

Compare Group 1 metals and transition metals

Answer 32

Group 1 metals and transition metals are heat and electricity conductors. They are 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 33

State three common characteristics of transition metals

Answer 33

- Ions with different charges - Coloured compounds - Catalytic propertie

Question 34

What is a catalyst?

Answer 34

A catalyst is a chemical substance that increases the rate of a chemical reaction. It is not used up over the course of the reaction.

Question 35

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

Answer 35

Crimson-red, Li Yellow-orange, Na Lilac, K

Question 36

Describe the properties of noble gases. Discuss the trend in boiling point down the group

Answer 36

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.