Periodic Table Trends Flashcards
Define ionisation energy.
The energy required to remove the most loosely held electron from one mole of gaseous atoms of an element.
What is the periodic table trend with ionisation energy?
Increases left to right across a period as each successive element has one more proton in its nucleus and one more electron in its valence shell. The distance between the valence shell electrons and the nucleus does not change and there for the +/- attraction increases.
Decreases down a group since the valence electrons are getting further away from the nucleus and are shielded from the full positive force of the nucleus by the filled shells closer to the nucleus.
Define electronegativity.
The ability of an atom to attract electrons towards it nucleus. Electronegativity refers to the electron attracting power of an atom when bonding.
What is the periodic table trend with electronegativity?
Increases from left to right across a period because the number of positive and negative charges is increasing resulting in greater +/- attraction.
Decreases down a group as the valence shell becomes increasingly
further away from the nucleus resulting in weaker attraction between the nucleus and an electron beyond the valence shell.
What is the periodic table trend for atomic radius?
Decreases from left to right across a period because each successive element has more protons and electrons than the one before. As the strength of the +/- attraction increases the valence electrons are attracted more strongly to the nucleus and the atomic radius shrinks.
Increases down a group because each successive element has its valence electrons in an energy shell that is further away from the nucleus.
What is the periodic table trend with metallic character?
Decreases from left to right across a period.
Increases down a group.
What is the periodic table trend with electron affinity?
Increases from left to right across a period.
Decreases down a group.
Define electron affinity.
The ability of an atom to accept an electron.
What is the periodic table trend with valence shell electrons?
For Groups 1, 2 and 13 to 18 the number of valence shell electrons can be predicted. Group 1 = 1, Group 2 = 2, Group 13 = 3, Group 14 = 4, Group 15 = 5, Group 16 = 6, Group 17 = 7 and Group 18 = 8.
