CHEM 101 Exam 2 UNCW (Turner)

fall semester 2026

In order to understand the behavior of electrons…

you must also understand the location or arrangement of electrons.

Quantum

smallest quantity of energy that can be emitted/absorbed in electromagnetic radiation

Wavelength

Distance b/w identical points on successive waves. Represented by a T ish L.

Frequency

number of waves that pass through a particular point in 1 second. Represented by a V

Electromagnetic Radiation

radiation or wave lengths and frequencies that exist. (1 for electric field, 1 for magnetic field) at a constant speed.

If you have a short, small wavelength, what is the frequency?

High

What is the speed of light?

3.00 x 10^8 m/s

Equation for wave behavior

speed of light = wavelength x frequency. (C =T x V)

Equation for particle behavior?

energy = VH or energy = hc/t. c = speed of light h=planks constant

Particle behavior is…

a stream of photons ( a stream of particles)

Photoelectric effect

threshold frequency dictates whether electron is ejected from metal surface

electrons that absorb energy are in what state

excited state

electrons that are not excited are in what state

ground state

Emission spectrum

pattern based on an atom developed when light passes through a prism (producing spectra in the gas phase)

Emission

releasing energy stored in light

Quantum numbers are a map for

a single electron around the atom

Principal Quantum #’s definition

energy level

A principle quantum number means that

the higher n the farther from the nucleus it. That means that there is more energy and more electrons.

Angular Momentum definition

shape of atomic orbital (# of them) it gives the subshell

Magnetic Quantum # definition

orientation of orbital

when electrons spin, what kind of properties do they have?

magnetic

Electron Configurations

a map for all of the electrons around the atom

Pauli exclusion principle

electrons in the same atom can not have the same 4 quantum numbers

Aufbau principle

lower subshells must be filled first

Hunds rule

all degenerate (same energy) orbitals must contain one electron with the same spin before adding a second

what do the electron configurations tell you?

the highest energy orbital for each energy level.

Cation

ion with a positive charge

isoelectronic

atoms or ions with the same electron configuration

anion

ion with a negative charge

valence electrons are the sum of…

s and p orbitals

Valence electrons

group # on periodic table

Inner core electrons or sigma

beginning of electron configuration

z

number of protons

z eff

z - sigma