3.2.1 - Periodicity (AS) Flashcards
What happens down a group?
a) Number of main electron energy levels
b) Shielding
c) Nuclear charge
d) Atomic radius
a) Number of main electron energy levels increases
b) Shielding increases
c) Nuclear charge increases but due to shielding, the EFFECTIVE nuclear charge DECREASES
d) Atomic radius increases
What happens across a period?
a) Number of main electron energy levels
b) Shielding
c) Nuclear charge
d) Atomic radius
a) Number of main electron energy levels stays the same
b) Shielding stays the same
c) Nuclear charge increases
d) Atomic radius decreases
From right to left, name the blocks of the periodic table
s, d, p (and f, below)
What kind of elements are in the s-block?
Alkali metals and alkaline earth metals
What kind of elements are in the d-block?
Transition metals (generally - see definition)
What kind of elements are in the p-block?
Noble gases (8); Halogens (7); post-transition metals; non-metals and metalloids
Are all d-block elements the same kind of metal?
No: not all d-block elements are TRANSITION metals, as not all form stable ions with a partially filled d-sub shell
What is a metalloid?
An element that shows a combination of characteristics of both metals and non-metals (e.g. Si, silicon)
Metals: reactivity _______ down a group
Increases (more easily lose electrons)
Non-metals: reactivity _______ down a group
Decreases (less easily form covalent bonds)
Period 3 - what bonding occurs with these elements? Na Mg Al Si P S Cl Ar
Na -> Na+ = ionic Mg -> Mg2+ = ionic Al -> Al3+ = ionic Si -> Macromolecular/giant covalent P -> P4 (covalent) S -> Si8 (covalent) Cl -> Cl2 (covalent) Ar -> Ar (monoatomic)
Example of a compound formed by silicon?
Silica/silicon dioxide, SiO2 (macromolecular)
