Aleks Placement Test: Chemistry

Matter

Anything that has mass and takes up space; made of atoms

Atoms

Basic unit of matter which cannot be broken down and contain mostly empty space; contains three parts: the electron, proton, and neutron

Elements

A pure substance that contains only one type of atom

Compound

Two or more elements that are chemically bonded; includes ionic and covalent

Mixture

Two or more substances that are together but not bonded

Pure Substance

Substance that contains only one kind of compound

Bose-Einstein Condensate

The state of matter with the lowest energy; basically a very cold solid

Solid

A state of matter with strong bonds

Liquid

A state of matter with weak bonds

Gas

A state of matter with no bonds

Plasma

The state of matter with the highest energy; it uses ionization instead of bonds

Robert Boyle

First to define an element; any substance is a substance unless it can be broken down

John Dalton

Used and combined previous ideas to discuss the atom; elements are made of atoms; all atoms of an element are identical; atoms of different elements are different; law of constant composition; atoms are invisible

Law of Constant Composition

Atoms of one element can combine with other elements to form compounds; a given compound always has the same relative numbers and types of atoms

J.J. Thomson

Discovered electrons and protons and developed the plum pudding model of an atom

Electrons

The negatively charged particle in an atom; circles around the nucleus in the electron cloud

Proton

The positively charged particle in an atom; located in the nucleus; determine the element

Neutron

The neutral particle in an atom; it has no charge and is located in the nucleus

Plum Pudding Model

A model of the atom that depicts a sphere of positive charge with electrons scattered throughout

Ernest Rutherford

Conducted an experiment in which he shot alpha particles at gold foil; roved there was a small, dense nucleus with a positive charge and that protons are positive

Metals

Elements located on the left side of the periodic table that want to lose electrons

Characteristics of Metals

- Malleable

- Ductile

- Conductive

- Lustrous

Malleable

The ability to be molded into shapes

Ductile

The ability to be pulled into wire

Conductive

The ability to allow heat or electricity to pass through an object

Lustrous

The ability to be shiny

Nonmetals

Elements located on the right side of the periodic table that want to gain electrons

Metalloids

Elements placed in a stair-step line between metals and nonmetals; they have characteristics of both

Diatomic Molecules

Elements that occur in pairs in their natural state; hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine

Electronegativity

The ability of a molecule to attract electrons to it; increases as you move left to right in the table and decreases as you move top to bottom; fluorine is the hardest

Atomic Radius

The radius of an atom; decreases as you move left to right and increases as you move top to bottom

Ionization Energy

The energy needed to rip off an electron; increases as you move left to right and decreases as you move top to bottom

Ion

An atom that has gained or lost electrons

Anion

An atom that gains electrons and has a negative charge; nonmetals

Cation

An atom that looses electrons and has a positive charge; metals

Isotope

An atom that has changed its number of neutrons

Atomic Number

A unique number to each element that tells the number of protons and the number of electrons if the atom is neutral

Atomic Mass

A number that tells the number of protons and neutrons in an atom

Neutron Number

Atomic Mass - Atomic Number

Radioactive

A nucleus that spontaneously decomposes, forming a different nucleus and producing one or more particles; alpha, beta, and gamma ray

Alpha Particle

One type of radioactive particle; it is a essentially a helium nucleus; when this type of particle is released, the mass of the atom is conserved and so is the atomic number

Beta Particle

One type of radioactive particle; it is essentially an electron; when this type of particle is released, the atomic mass is conserved and the atomic number gains one (a neutron is changed to a proton)

Gamma Ray

One type of radioactive particle; it is a high energy photon of light and is used to release excess energy; the atom is not changed at all

Half-Life

The time required for half of the original sample of nuclei to decay; each radioactive nucleus of the same element has the same half-life; the shorter the half-life, the more likely a nucleus will decay

Percent Abundance

Elements exist naturally in different isotopes, to the atomic mass listed on the table is an average

Percent Abundance Equation

Average Mass = (%)•(Mass of Isotope A) + (%)•(Mass of Isotope B) +...

Crest

The highest point of a wave

Trough

The lowest point of a wave

Wavelength

The distance between the crests of a wave; symbol is lambda

Frequency

The number of waves that pass through a point in a given time; symbol is nu

Amplitude

The height of a crest or trough; crest to the zero line; absolute value

Speed

How fast a wave travels in a given distance

Node

Point on a wave where the wave returns to the zero line; a crest or trough is trapped between the two points

Electromagnetic Spectrum

The range of wavelengths or frequencies over which electromagnetic radiation extend

Visible Light

White light is passed through a prism and creates all visible colors; each color has its own frequency and wavelength

Atoms and Colors

When an atom is excited by energy it gives off its own characteristic colors of light

Photon

A light particle

Speed of Light Equation

C = w•f

C is the speed of light

w is wavelength in meters

f is frequency in hertz

Speed of Light

3.00•10^8m/s

Continuous Spectrum

Broken bands of colored light

Bright Line Spectrum

a.k.a. emission spectrum; occurs due to the energy an electron gives off as it travels from high to low energy; fireworks

Dark Line Spectrum

a.k.a. absorption spectrum; occurs due to the energy that an electron gains as it travels from low to high energy

Energy using Planck's Constant

E = h•f

E is energy

h is Planck's constant

f is frequency in hertz

Planck's Constant

6.626•10^-34 Joules/hertz

Wave-Particle Duality of Light

Light sometimes acts like a particle and sometimes like a wave

Wave-Mechanical Model of the Atom

A model of the atom in which the orbitals are nothing like orbits

Heisenberg Uncertainty Principle

It is impossible to know the exact position and momentum of an electron at the same time

Quantum Theory for an Atom

The probability of finding electrons in certain regions of an atom is described by orbitals

Atomic Orbital

A region around the nucleus of an atom where an electron with a given energy may be found 90% of the time; 4 types: s, p, d, and f

N

The principal quantum number; tells us which energy level an electron is found in, the maximum number of electrons that can be found in one energy level, and the size of an electron cloud

L

The orbital quantum number; tells us the shape of the orbital (s,p,d,f)

M

Quantum number that tells us the orientation of the orbital in space

S

Quantum number that tells how an electron spins in an orbital

Pauli Exclusion Principle

A rule that states that each electron has its own unique set of quantum numbers and that two electrons with the same spin cannot occupy the same orbital and that an orbital can only hold two electrons

S Orbital

The orbital with the lowest energy; it has one orbital and can hold two electrons

P Orbital

The orbital with the second lowest energy; it has three orbitals and can hold six electrons

D Orbital

The orbital with the second highest energy; it has five orbitals and can hold ten electrons

F Orbital

The orbital with the highest energy; it has seven orbitals and can hold 14 electrons

Hund's Rule

Each suborbital will fill with one electron before accepting a second electron

Kernel Structure

Electron configuration shorthand

1. Find the noble gas that comes before the element

2. Write the gas in brackets

3. Determine energy level and orbital you are starting on

4. Follow the energy pyramid

Valence Electrons

Electrons on outer most orbital; always the highest energy 's' and 'p' orbital

Oxidation State

The electrons an element will gain or lose in order to become stable (8 electrons)

Acids

Always start with hydrogen; donate a proton in a solution

Oxyacid

Acid that has an oxygen

Organic Acid

Acid that contains a carbon atom

Diprotic Acid

Acid that has 2 hydrogens to donate

Triprotic Acid

Acid that has 3 hydrogens to give

______ate

______ic acid

_______ite

_______ous acid

Methane

1 carbon

Ethane

2 carbon

Propane

3 carbon

Butane

4 carbon

Pentane

5 carbon

Hexane

6 carbon

Heptane

7 carbon

Octane

8 carbon

Nonatne

9 carbon

Decane

10 carbon

Alcohols

Subtract a hydrogen and add a -OH group; add ol to end of name