Applied Science AQA/Periodic Table

Topic Title

Context

The patterns evident in the Periodic Table enable industrial and research and development chemists to predict properties and potential new applications of elements, from the inert nature of the noble gases to semiconductor properties of Group 4 (14), to the many applications and uses of the transition metals.

Syllabus content	What you need to do
• that the Periodic Table lists elements in increasing order of proton number • how each row is equivalent to the filling of an electron shell up to two (in row 1) or eight electrons • how each column or group contains elements with the same number of outer shell electrons and thus similar chemical properties • how each row begins with a highly reactive alkali metal (Group I) and ends with a noble gas (Group 0 (18)) • how, across a period (row), properties of elements change from metallic to non-metallic
• the properties (including radii, ionisation energy and electronegativity) of: • the s-block elements • the d-block metals (including the transition metals and their coloured compounds in solution) • Group VII (17), the halogens • Group 0 (18), the noble gases.

Exploration of key ideas (must be original text, not C&P) – level checked by AQA

In general, point students towards the approach to take, as opposed to just giving them information.

Periodic table facts

The periodic table is arranged according to atomic numbers.
The atomic number of each element tells us the number of protons it contains.
Anything in the same group has the same number of electrons in their outer shell.
Anything in the same group has the same chemical properties and they all react the same way.
Anything in the same period has the same number of shells.

Group 0

Highly unreactive, reactivity increases as you go down the group.
They have a full outer shell, the atoms have more electrons and shells.
React by giving away electrons.
Electronegativity decreases down the group, less attraction present.
They are colourless gasses, sometimes known as the noble gasses.
The atomic radii gets larger going down the group.
Ionisation energy decreases down the group, electrons are further away from the nucleus therefore easier to move.

Ionisation energy

The intramolecular forces need to be broken for the substance to melt or boil, only a small amount of energy is needed to break the bond.
Force is weak, the atoms are held together by weak intramolecular forces.
Melting and boiling temperature increases as the atoms get larger going down the group.
They hold atoms in their place next to each other.
Larger molecules have a larger intramolecular force, more energy is needed to break them.

Group 1 and Group

Group 1 metals react with water.
The attraction to the nucleus is less.
The reactivity of the alkali metals, increase down the group.
Atoms become larger.
Outer electron is further away from the nucleus.
The electron is lost more easily and the element is more reactive.

Electro Negativity

Electronegativity increases going across the table, because more protons are added to the nucleus, this makes it more positive and attractive to electrons.
The power of an atom to attract electron density in a covalent bond towards itself.
Most Flurein least is Bottom of group 1.

Ionisation Energy

The first ionisation energy of an element is the energy required to remove one mole of electrons to one mole of gaseous atoms.
The ionisation energy decreases down the group. The electron is further away from the nucleus, it has less attraction to the electron making it easier to move.
There is more shielding from the inner shells of electrons and this also decreases the attraction of the nucleus.

Group 7

The attraction between the nucleus and electron increases when they are able to get close.
Atomic radii increases going down the group.
Harder to attract electrons to larger atoms because of distance to the nucleus is larger and more shielding
Ionisation energy and electronegativity decreases going down the group.
Smaller atoms more readily attract electrons to themselves.
Reactivity decreases going down the group. Elements lower down are less reactive.
Electrons are attracted toi the nucleus.

Metals

Sonourous - make a nice noise.
Magnetic, only iron, nickel and colbalt.
Conducts heat and electricity.
Mercury - liquid.
Strong, hard and solid.
Reflective and shiny.
Ductile - stretch into wires and wont snap.
Malleable - change shape.
Have a high melting and boiling point.

Non-Metals

Brittle.
Metaloids - mix with other properties.
Look metallic.
Can be solids, liquids or gasses.
Poor at conducting heat and electricity.

Study task

1. What causes the trend in first ionisation energy from left to right across the table?

A) Greater number of electrons

B) Greater shielding

C) Increased nuclear charge

Answer is: c

2. Which is most soluble in water?

A) Mg(OH)2

B) Ba(OH)2

C) Ca(oh)2

Answer is: b

3. What causes the largest changes in melting point across period 2 elements?

A) Change in bonding structure

B) Greater electronegativity

C) Increase in nuclear charge

Answer is: a

Careers and organisations

Carry out some research into these jobs in this area. (Feel free to add other jobs you find.)

Research these roles:	What are the benefits of this role to society?	What organisations would employ someone in this role? (Where would they work?)	What would someone in this role have to do within the organisation?	What scientifically-related skills do they need to have? What techniques do they need to have mastered?	What experience is needed to undertake this role and its responsibilities within an organisation?	What other science personnel will they work with in their organisation.
Job 1
Job 2

Relevant practical/s

– relating to criteria skills

Quick questions

Example:

quick questions

Solution

click to reveal answer

Exam-style questions

– can we use old AQA qs… e.g. from more than 5 years ago? With Examiner comments

Solution

click to reveal answer

Links

to other sections within this book

to good external websites (including AQA website, wikipedia, relevant applications / companies) - also considering links in spec

References / Bibliography

of recommended text books

including mapped refs to existing books

Back to Contents