Across chemical groups, elements are generally organized according to their chemical mass with the execption of a couple spots. If you study the Periodic Table of elements than the first trend you would notice is that the atomic number rises by one each time. Down periods, trends occur such as elements in a colmn are organized by their properties.
Electronegativity and ionization energy increases as one goes up a group and right across periods. Ionic radius increases while atomic radius decreases as one goes across periods from left to right.
one atom is bigger than the other
1. In a period is a trend of decrease from left to right but it is not absolute.2. In a group the atomic radius increase moving down.
The density increase down.
Melting Point
Electronegativity decrease down in a group.
Within a group, the number of shells (or energy level) increases (as we go from top to bottom of a group) and hence the size of the atom or the atomic radii increases.
The boiling point decrease from lithium to caesium.
1. In a period is a trend of decrease from left to right but it is not absolute.2. In a group the atomic radius increase moving down.
1. In a period is a trend of decrease from left to right but it is not absolute.2. In a group the atomic radius increase moving down.
Adding more electrons that need to occupy higher energy orbitals
The atomic mass increases down a group.
The density increase down.
Melting Point
Electronegativity decrease down in a group.
Atomic radius increases down the group
The trend of atomic radius increases down a group on the periodic table. This occurs because each successive element down a group has another energy level. As more electrons are added, more energy levels are needed to hold the electrons.
It increases as you move to the right or go down
Within a group, the number of shells (or energy level) increases (as we go from top to bottom of a group) and hence the size of the atom or the atomic radii increases.