2.3- tends in the periodic table part 2

Question 1

what is the first ionisation energy?

Answer 1

energy required to remove one electron from an atom of an element in the gas phase

Question 2

trend of ionisation energy

Answer 2

down a group = decreases

left to right across period = increases

Question 3

what is chemical reactivity?

Answer 3

ease with which an element undergoes a reaction

• metals lose electrons
• non metals gain electrons

trend left to right across periods = elements change from metals to metalloids (semi-metals) to non metals

Question 4

trend in chemical reactivity for metals

Answer 4

down a group = increase

across a period = decreases

Question 5

trend in chemical reactivity for non metals

Answer 5

down a group = decreases

across a period = increases

Question 6

what are the two key ideas that explain many trends in the physical properties of elements in the periodic table

Answer 6

• left to right across period = core charge increases, attractive force felt between valence electrons and nucleus increases
• down a group = number of shell in atom increases = valence shells further away from nucleus = held together less strongly.