AP CHEM - Atomic Structure and Periodicity

What do we mean when we say something is quantized?

It means that elements absorb a unique of energy.

In the Bohr model of the hydrogen atom, what is quantized?

Elements are quantized.

Photon

Particle of light and discrete bundle of energy.

Quantum number

Energy state of electron

Ground state 

The lowest energy state of an electron in an atom, where it resides at its closest distance to the nucleus.

Excited state

The condition of an electron when it has absorbed energy and moved to a higher energy level, further from the nucleus.

Why do we emphasize the valence electrons in an atom when discussing atomic properties?

We emphasize valence electrons because they are primarily responsible for an atom's chemical behavior and bonding with other atoms.

What is the relationship between valence electrons and elements in the same group of the periodic table?

Same # of valence electrons, same in a family, same reactivity. 

In defining the sizes of orbitals, why must we use an arbitrary value?

The uncertainty principle. It accounts for the part that may be excited.

Atomic Radii

The distance from the nucleus to the outermost electron. Decreases from left to right.

Ionization Energy

The energy change associated with the addition of an electron to a gaseous atom. 

Electron Affinity

The energy change associated with the addition of an electron to a gaseous atom.

Electronegativity

An elements tendency for an atom to attract electrons to itself when it is chemically combined with another element. Decreases from top to bottom, increases from left to right.

If there are higher energy levels, what would happen to Coulombic Force?

It would be weaker. 

What are inside the nucleus?

Protons and neutrons.

Where do electrons reside?

Outside of the nucleus.

What happens to charge when protons increase? 

Charge becomes more positive. 

Why is oxygen smaller than nitrogen?

It has an additional proton. Coulombic Force of O is greater than N, therefore the radius is smaller.

Ionization Energy

How easy it is to remove an electron.

Big element

Low Coulombic force, higher ionization energy

Electron affinity in bigger atoms

Small

Smaller atom accepts

more electrons due to higher Coulombic Force

Atoms w/ low electronegativity 

Want to give up electrons

Polar covalent bond

Electrons favor one side

Nonpolar covalent bond

Electrons shared equally

Metals tend to be big 

Nonmetals tend to be small

Smaller atom

Higher control over electrons, higher Coulombic force