AP Chem - Unit 1

What is effective nuclear charge?

A measure of the protons pull on the outer shell e-

What is first ionization energy?

The energy required to remove a ve- from an atom in a gaseous form

What is the period trend of the first ionization energy?

Increases because greater nuclear charge is because of more p+ (FOA), so the e- and p+ pull each other more, so it takes more energy to remove a ve-

What is the group trend for first ionization energy?

Decreases down a group bc greater e- distance reduces FOA, so it takes less energy to take away the e-

What is the atomic radius?

Average distance from the nucleus to the outermost e-

What is the period trend for atomic radius?

Decreases bc a greater nuclear charge causes more FOA, so the p+ and e- pull eachother more closesly, reducing the size of the atom

What is the group trend for atomic radius?

Increases because because more e- shells increases the distance between p+ and e-, reducing its FOA, so they won’t pull each other as closely, leading to a bigger atom

What amount of p+ must the smallest ion have?

the most

What amount of p+ must the largest ion have

the least

What is electronegativity?

A measure of how well an atom can attract an electron

What is the period trend for electronegativity?

Increases because a greater effective nuclear charge allows it to attract electrons easier

What is the group trend for electronegativity?

Decreases because more e- distance reduces FOA, makes it not attract e- as easily

What is binding energy?

The total energy needed to break a bonded system

What is the Aufbau Principle?

Fill the lowest energy orbital first

What is Hund’s rule?

Orbitals of equal energy fill 1 at a time

What is Pauli Exclusion Principle?

Arrows must have opposite spins in an orbital

How to figure out an element’s effective nuclear charge?

Atomic number - inner shell e-’s

What is shielding?

Inner shell e- block postive pull of the nucleus on the outer ve-

What is e- repulsion?

Physical force that occurs when e- repel each other because like charges repel

What is e- affinity?

The amount of energy released when an e- is added to a netural atom

What is the period trend for e- affinity?

It increases because more protons increase FOA, so e- are more favorable, releases energy, has a higher ability to attract e-

What is the group trend for e- affinity?

It decreases because more distance for more e- shells decreases FOA, so it attracts e- less easily, less favorable, takes energy

What are successive ionization energies?

The amount energy to remove more e- after IE

What is ionization energy?

The energy required to remove a ve-

What is the period trend for ionization energy?

Increases bc more protons increases FOA between e- and p+ needing more energy to pull the ve-

What is the group trend for ionization energy?

Decreases bc more electron shells increases the distance between p+ and e-, decreasing FOA, making them easier to pull, needing less energy to do so

What is ionic radii?

Positive atoms have a smaller atomic radius because more FOA

Negative ions have a larger atomic radius because less FOA

What is the isoelectronic series?

A group of elements/ions that have the same number of e-, same e- configuration

What is a Coulombic Attraction?

1. 1. Amount of charge = more charge is more FOA

2. 2. Distance between charges= more distance is less FOA, less distance is more FOA