Periodic Trends

Why does metallic character decrease as you move across a period?

As you move across a period, it becomes increasingly easier for the atom to gain electrons to attain stability rather than lose electrons.

What happens to the atomic radii as you move across a period?

As you move across a period, the atomic radii decreases.

What happens to the first ionization energy as you move across a period?

As you move across a period, the first ionization energy increases.

What happens to the atomic radii as you move down a group?

As you move down a group, the atomic radii increases.

Why does metallic character increase as you move down a group?

As you move down a group, the atomic radius increases and the effective nuclear charge on the valence electrons decreases making it easier for them to leave the atom.

What happens to the first ionization energy as you move down a group?

As you move down a group, the first ionization energy decreases.

What are the exceptions to the electron affinity trends?

1. Among nonmetals the first period has lower electron affinities than the elements below them in their respective groups 2. Elements with configurations of Xs2, Xp3, and Xp6 have electron affinities less than zero beause they are unusually stable; These elements require the input of energy in order to gain electrons

Why are anions larger than their respective atoms?

1. Electron-electron repulsion forces pull them further apart. 2. Electrons outnumber protons; protons cannot pull extra electrons as tightly toward the nucleus.

Why are cations smaller than their respective atoms?

1. Less electron-electron repulsion so they can come closer together. 2. Protons outnumber electrons; protons can pull the fewer electrons toward the nucleus more tightly. 3. If the electron that is lost is the only valence electron, then the electron configuration is like that of a noble gas, then an entire energy level is lost. In this case, the radius of the cation is much smaller than its respective atom.

What is the relationship between anions and their respective atoms?

Anions are larger than their respective atoms.

Why does atomic radii decrease as you move down a period?

As you move across a period, electrons are added to the same energy level while protons are also being added. The concentration of more protons creates a higher effective nuclear charge.

What families are the exceptions to the first ionization energy trend?

Boron and oxygen

What is the relationship between cations and their respective atoms?

Cations are smaller than their respective atoms.

First Ionization Energy

Energy required to remove the highest energy electron from a neutral atom in its ground state.

What is the order of the families in the first ionization energy trend? (Least amount of ionization energy to highest)

Li, B, Be, C, O, N, F, Ne

Metallic Character

Metals losing valence electrons easily

Anions

Negative ions

Cations

Positive ions

Atomic Radii

Radius of an atom

When do subsequent ionization energy increase greatly?

Subsequent ionization energies increase greatly once an ion has reached the state like that of a noble gas; It becomes very difficult to remove an atom once it loses enough electrons to lose an entire energy level so that its valence shell is filled.

Why does first ionization energy increase as you move across a period?

The atomic radii (size of the atom) becomes smaller as you move across the period because there is a progressively higher nuclear charge. This makes it harder to remove the outermost electron.

What happens to electron affinity as the you move down a group?

The electron affinity decreases

What happens to electron affinity as you move across a period?

The electron affinity increases.

What happens to electronegativity as you move down a group?

The electronegativity decreases as you move down a group.

Why does electronegatvity decrease as you move down a period?

The electronegativity decreases because the effective nuclear charge decreases as you move down a group.

What happens to electronegativity as you move across a period?

The electronegativity increases as you move across a period.

Why does electronegativity increase as you move across a period?

The electronegativity increases because the effective nuclear force increases as you move across a period.

Why does the first ionization energy decrease as you move down a group?

The electrons that are being removed are the furthest from the nucleus. The effective nuclear charge on that electron is least the making it easier to remove the electron from the atom.

Electron Affinity

The energy given off when a neutral atom in the gas phase gains an electron to form a negatively charged atom.

What happens to metallic character as you move across a period?

The metallic character decreases as you move across a period.

What happens to metallic character as you move down a group?

The metallic character increases as you move down a group.

Why does atomic radii increase as you move down a group?

The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is farther from the nucleus than the previous one. Therefore, the atomic radius increases as the group and energy levels increase.

Electronegativity

The tendency of an atom to attract electrons