Trends of the periodic table

Question	Answer
Does ionization increase or decrease across a period? WHY?	Ionization increases because nuclear charge increases therefore the electrons in the outer energy levels will be more tightly held and more difficult to remove.
Does ionization increase or decrease going down a group? WHY?	As we go down a group, there are more energy levels added. This makes the very outer electrons move further away from the nucleus. This results to a weaker attraction which makes them easier to remove. Therefore ionisation decreases.
Does atomic size/ atomic radius increase or decrease going DOWN A GROUP? Why?	Atomic size increases going down a group due to the increase in the number of electron shells.
Does atomic size/ atomic radius increase or decrease going ACROSS A PERIOD? Why?	Atomic size/ covelant radius decreases going across a period because nuclear charge increases, this pulls the electron shells closer to each other.
What is the shielding/ Screening effect ? What does it suggest?	The electrons in the electron shells will shield those in the outer shells from the attraction of the nuclear charge.
What does the screening effect suggest?	The screening effect suggests that as the atoms gets bigger and have a greater number of shells, it takes less energy to remove electrons.

Resource summary

	Created by Stefanie Doukakis about 5 years ago