Applied Science AQA/Periodic Table

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.

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
Electro Negativity Ionisation Energy
 * 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.
 * 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.
 * 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.

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.)

Relevant practical/s
– relating to criteria skills

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

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

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