Chemistry Unit One

Electron Configuration

The arrangement of electrons in orbitals of an atom

How many electrons can an s subshell hold?

2

How many electrons can a p subshell hold?

6

How many electrons can a d subshell hold?

10

How many electrons can f orbitals have

14

Pauli Exclusion Principle

No two electrons can share the same four quantum numbers. These means orbitals can only hold two electrons spinning in different directions.

Hund’s rule

Electrons will only share an orbital if all other orbitals of the same energy level have electrons in them.

Diamagnetic

Atoms with all electrons paired. They are repelled by magnetic fields.

Paramagnetic

Atoms with unpaired electrons. They are attracted to magnetic fields.

Noble gas core

The completed shell configuration of a noble gas. They are used to abbreviate the electron configuration of other atoms.

Transition metals

Elements that readily gain or lose electrons in their d shells.

Effective nuclear charge

The magnitude of positive force felt by electrons. Increases from left to right on the period table.

Shielding

When the effective nuclear charge felt by an electron decreases due to repulsion by other electrons

Atomic radius

The distance between the nucleus of an atom and its valence shell. Decreases from left to right and increases from top to bottom on the periodic table.

Ionization energy

The energy necessary to remove an electron from its nucleus. Generally increases from left to right on the periodic table, and after multiple ions have been removed or separating ions from complete shells.

Cation

An ion with a positive charge

Ion

An atom that has lost or gained electrons so that it is no longer neutrally charged

Electron affinity

Energy released when an atom accepts an electron. Increases from left to right on the periodic table.

Anion

An ion with a negative charge

Metallic Character

A property quantifying the metallic properties of an element. Decreases from left to right and increases from top to bottom on the periodic table.

Diagonal relationships

Elements that are diagonal to each other on the periodic table usually share similar properties.

Isoelectronic

Ions and atoms with the same number of electrons

Ionic radius

The distance between an ion’s nucleus and valence electrons. Increases when an ion gains electrons and decreases when an ion loses electrons.

Correct order of large SI prefixes (largest to smallest)

Tera, giga, mega, kilo

Correct order of small SI prefixes (largest to smallest)

deci, centi, milli, micro, nano, pico

Celcius to Kelvin

C+273.15=k

Celcius to Farenheit

9c/5+32=f

significant figures

The number of numbers in a quantity (including zeros after decimal)

Density equation

d=m/v

Adding/subtracting sig figs

round to the last decimal place of number with the least amount of decimals

Multiplying/dividing sig figs

round to the amount of sig figs that the number with the least sig figs has

accuracy

how close measurements are to the true value

precision

how close measurements are to each other

mixture

a combination of two or more substances where each substance retains its identity

homogeneous mixture

a mixture where the substance is uniform throughout

heterogeneous mixture

A mixture where the composition is not uniform

conversion factor

a fraction in which the same quantity is expressed one way in the numerator and another way in the denominator

physical property

properties that can be observed without changing the identity of a substance

chemical property

properties observed during chemical reactions

extensive property

properties that depend on the amount of matter a substance has

intensive property

properties that don’t depend on the amount of matter a substance has

protons

subatomic particles with a positive charge

electrons

subatomic particles with a negative charge

neutrons

subatomic particles with no charge

atomic number

the number of protons an element has

mass number

the number of protons and neutrons in an atom

metal

an element that conducts heat and electricity

non-metal

an element that does not conduct heat and electricity

metalloid

an element that shares properties with metals and non-metals

avogadro’s number

6.0221×10²³

Equation for kinetic energy

E_k=mv²/2

electrostatic energy

energy between two particles

coulomb’s law

E_el=Q₁Q₂/d

Joule

kgm²/s²

Order of electromagnetic spectrum (long wavelength to short wavelength)

gamma, x-ray, ultraviolet, visible light (violet to red), infrared, microwaves, radio waves

wavelength

the distance between two identical points on a wave

frequency

number of waves per second

What happens to frequency when wavelength is increased?

decreases

what happens to energy when frequency is increased

increases

what happens to wavelength when energy increases

decreases

amplitude

distance from the midline to the peak of a wave

speed of light

3.0×10⁸m/s

constructive interference

when waves combine in phase and strengthen

destructive interference

when waves combine out of phase and weaken

blackbody radiation

radiation emitted from heated solids

quantum

the smallest amount of energy that can be emitted or absorbed in the form of electromagnetic radiation

Plancks Equation

E=hv

Planck’s constant

6.63×10^-34Js

Photon

subatomic particles of light that have particle and wave-like properties

Emission spectra

light emitted by a substance in an electronic state

Rydberg Equation

1/m=R(1/n₁²-1/n₂²)

Rydberg constant

1.097×10⁷m^-1

What happens to an electron’s energy as it moves away from the nucleus

increases

Equation for calculating the change in energy between electron states

E=-2.18×10^-18J(1/n_f²-1/n_i²)

What if a particle is smaller than its De Broglie wavelength?

It must be modeled using quantum physics

De Broglie wavelength equation

wavelength=h/mv

Heisenberg principle

it is impossible to simultaneously know the momentum and position of an electron

Electron density

The probability that an electron can be found in a certain area

Quantum numbers

numbers that denote which orbital an electron is in

quantum number n

Then quantum number that designates an electrons distance from the nucleus

quantum number l

the quantum number that designates the shape of an orbital

possible values for quantum number l given quantum number n

0…(n-1)

quantum number m_l

the quantum number that designates the orientation of an orbital

possible values for quantum number m_l given quantum number l

-l…l

quantum number m_s

the quantum number that designates the directional spin of an electron

possible values for quantum number m_s

-1/2 and 1/2

correct order of p orbitals

s, p, d, f

s orbital shape

sphere

p orbital shape

“dumbbell” shaped with a node in the middle