Unit 3-Quiz Flashcards
Period trends
The pattern for a horizontal row on the periodic table (left to right)
Group trend
The pattern for a vertical column on the periodic table (up and down)
Atomic radius
The measure of the size of an atom
measured from the nucleus to the outermost electrons
Period trend for atomic radius
As you move across a period (left to right) atomic radius decreases
Group trend for atomic radius
As you move down a group, the atomic radius increases
Why does the atomic radius decrease as you move across a period?
As you move towards the right, the nuclear charge increases. The greater the nuclear charge, the more tightly a nucleus is holding onto the valence shell. Being more tightly packed means they are smaller
Why does the atomic radius increase as you move down a group?
Each time you move down a group, the atomic radius gets bigger because you add energy levels, therefore the outermost rings are far from the nucleus
Ion radius
The size of an atom
Positive Ion
Cations
When atoms lose electrons, they get smaller
Why do atoms get smaller when they lose electrons?
They lose their valence electrons, which means they have fewer energy levels
Negative Ions
Anions
When an atom gains electrons, it gets bigger
Why do atoms get bigger when they gain electrons?
When an atom gains electrons, it holds onto more electrons less tightly
Ionization energy
The energy required to remove an electrons from an atom
Period trend for ionization energy
As you move across a period, ionization energy increases
Why does ionization energy increase as you move across a period?
As you move across a period the nuclear charge increases. The greater the nuclear charge, the more tightly the atom holds onto the valence electrons. The greater the nuclear charge, the more energy it will take to remove an electron
