Unit 5: Electrons in Atoms

Electromagnetic radiation

A form of energy that exhibits wavelike behavior

Radiant Energy

Energy that travels in the form of waves that have both electrical and magnetic properties

Low energy, Safe EM radiation

• Radio waves

• Microwaves

• Infrared

• Visible light

High energy, dangerous EM radiation

• UV

• X-rays

• Gamma radiation

Speed of light

3.00 × 10⁸ m/s

• Lambda

• Wavelength

λ

• Nu

• Frequency

ν

E=h x v

Planck’s equation

Ground state

Lowest energy orbital

Excited states

Higher energy orbital

Electron cloud

The space around the nucleus where the atom’s electrons are found

2 electrons

The 1st energy level holds a maximum of __________

8 electrons

The 2nd energy level holds a maximum of __________

18 electrons

The 3rd energy level holds a maximum of __________

6.626 × 10^-34Jxs

Planck’s constant

Orbitals

The circular path in which electrons in an atom circle the nucleus in

Electrons absorb energy

How do electrons move to higher state?

They give off the energy they absorb as light waves

What do electrons do when they fall back to a lower energy state?

• Smallest

• Closest to the nucleus

The lowest energy level is _______

Energy levels

Spherical regions of space around the nucleus in which electrons are most likely to be found

Electron cloud

The space around the nucleus where the atom’s electrons are found

Valence electrons

The electrons in the outermost energy level

Aufbau principle

Each electron occupies the lowest energy orbital available

Pauli exclusion principle

Up to two electrons can occupy a single atomic orbital

Hund’s rule

Single electrons spinning in the same direction must occupy each equal-energy orbital before additional electrons with opposite spins occupy the orbital