Periodicity

Question 1

define periodicity

Answer 1

repeating pattern of trends across different periods

Question 2

why do elements of the same groups react in similar ways?

Answer 2

same outer shell configuration

Question 3

describe the trend in atomic radii across a period

Answer 3

-protons added to nucleus so nuclear charge increases
-electrons are added to the same shell
-nuclear attraction on outer shell electrons increase
-electron shells are drawn inwards by the nucleus so atom becomes smaller
-atomic radii decreases

Question 4

explain the trend in atomic radii down a group

Answer 4

-number of shells increases
-outer electrons are added to new shell further away from the nucleus
-shielding effect by inner electrons increase
-increased distance and shielding outweighs increase in nuclear charge
-so nuclear attraction on outer most electron decreases
-so atomic radii decreases

Question 5

describe the effect of bonds and structure on melting and boiling points

Answer 5

-if bonds breaking are strong bonds then the structure is giant so high mp/bp

-if bonds breaking are weak bonds then the structure is simple so low mp/bp