Look at the energy layer

Same structure -> look at the nuclear charge number

Same nucleus -> look at electrons

The energy required for a gaseous ground state atom to lose an electron and convert into a gaseous ground state positive ion.

Measure the difficulty of comparing the loss of electrons

Same cycle from left to right

Same family from top to bottom

The I1 of IIA and VA families is greater than that of the adjacent main families

explain

I1<I2<I3<···increase step by step

application

Determine the strength of (non-)metallic properties

Determine the valence

Determine whether the same energy level

electrons in an atom used to form chemical bonds

Describe the attraction of different atoms to bonding electrons

Unitless, relative value

Same cycle from left to right[&]

Co-owner family from top to bottom [m]

Determine the strength of (non-)metallic properties

Determine the positive or negative value of a chemical compound

Judging (non-)metals in general

Generally determine the key type