The Periodic Table in more detail

Question 1

The periodic table in more depth

Answer 1

• The periodic table is arranged in order of increasing atomic number into 7 rows (periods) and 18 columns (groups). The table can be divided into 4 blocks based on the number of electrons in the subshells. There are s, p, d and f blocks containing elements that are filling these subshells.

Question 2

Blocks

Answer 2

• Correspond to the electronic configuration.

- Indicate the subshell occupied by valence electrons.

Question 3

Atomic size

Answer 3

• Decreases from left to right due to increasing no. of protons in nucleus that pull in the electrons (attraction). Shell numbers stay the same.
• Increases down a group because each period adds an energy level and shells are added further away from the nucleus.

Question 4

Ionisation energy

Answer 4

• Energy required to remove an electron a gaseous atom. First ionisation energy is the energy required to remove the first (outermost) electron.
• Increases up a group as electrons are closer to positive nucleus and a stronger attraction means its harder to remove, thus more energy is required.
• Increases across a period, left to right, for the same reason.

Question 5

Electronegativity

Answer 5

• Measures the degree to which an atom attracts electrons to itself.
• FONCL (Fluorine, oxygen, nitrogen and chlorine) are the 4 most electronegative elements.
• It increases up a group and across a period from left to right.
• Non metals are considered to be more electronegative than metals because they gain electrons.

Question 6

Metalloids

Answer 6

• Metalloids show both metallic and non-metallic properties.

Question 7

Metallic character

Answer 7

• Increases down a group as outer shell electrons are further away thus less strongly attracted to the nucleus.
• Decreases left to right, which is determined by an atom’s ease in losing electrons. Across a period, metallic character decreases and the nuclear charge increases making it more difficult to lose electrons and form positive ions.

Question 8

Oxidising strength

Answer 8

• Oxidising strength is how readily an element gains electrons. Such elements are strong oxidants and themselves reduced.
• Oxidisation strength increases across a period and up a group.
• The strongest oxidants are at the top right corner of the periodic table (F and Cl).

Question 9

Reducing Strength

Answer 9

• Reducing strength is how readily an element loses electrons.
• The strongest reductants are at the bottom left corner of the periodic table (Na and K).