Chemistry Midterm Study Guide

An element is a pure substance that can not be broken down into simpler, stable substances and is made up of one type of atom.

Is an atom or group of bonded atoms that has a positive or negative charge.

Isotopes are atoms of the same element that have different masses. The isotopes of an element have the same number of protons and electrons but different number of neutrons.

An element is a pure substance that can not be broken down into simpler, stable substances and is made up of one type of atom.

Compounds are made from two or more elements in fixed proportions. Example; H2O.

The smallest unit of a substance that keeps all of the physical and chemical properties of the substance.

When electrons are transfered between elements. Formed by a metal (which loses e- and becomes a cation) and a nonmetal (which gains e- and becomes a anion). COMPOUNDS are formed.

Share electrons to form MOLECULES. Formed by two nonmetals bonding together.

Characteristics; shininess, metallic luster, the ability to conduct energy and transfer. Thus metals are good good electrical and heat conductor. Most metals have malleabilty (the ability to be hammered into thin sheets). They are also ductile meaning they can be rolled into wires.

The number of particles in a mole can be expressed; 6.022 x 10²³

A region in an atom where there is high probability of finding electrons.

States that mass is neither created nor destoryed during ordinary chemical reactions or physical changes.

States that s chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

States that if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers.

Is the distance between corresponding points on adjacent waves. The unit for wavelength is a distance unit.

Is a particle of elctomagnetic radiation having zero mass and carrying a quantum of energy. The energy of a particluar photon depends on the frequency of radiation.

Is the defined as the number of waves that pass a given point in a specific time, usually one second.

The lowest energy state of an atom is its ground state.

An excited atom returns back to geound state, it gives off energy it gained in the form of elctromagnetic radiation. We see photons in the form of a color.

A state in which an atom has a higher potential energy than it has in its ground state is an excited state.

The elements of group 1 of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium) are known as the Alkali metals.

The elements of group 2 of the periodic table (beryllium, magnesium, calcium, barium, and radium) are called the alkaline-earth metals.

The d-block elements are metals with typical metallic properties and are often referred to as transition metals.

The energy required to remove one electron from a neutral atom of an element.Across the Period: Increase. This increase is caused by increasing nuclear charge, the more electrons in your final shell the more energy it tkaes to get electrons.Down the Group: Decrease. The electons get farther away from the nucleus so it is easier to take away their electrons.

Any process that results in the formation of an ion is refered to as an ion.

A positive ion is known as a cation.

A nonmetal is a poor conductor of heat and electricty. Many nonmetals are gases at room temp. And if theyare solid they tend to be brittle.

Found between nonmetals and metals. A metalloid is an element that has some of the characteristics of nonmetals. All metalloids are solids at room temp. Metalloids are also known as semiconductors.

The vertical columns of the peroidic table are called families. They have similar characteristics.

The horizontal rows of elements in periodic table are called periods.

Chemistry is the study of the composition, structure, and properties of matter and the changes that matter undergoes.

An electron occupies the lowest energy orbital that can reieve it.

If two electrons occupy the same orbital then they must have opposite spin states.

Electrons are spread out in singulary occupied orbitals before a second electron is added.

The Group 18 elements (helium, neon, argon, kyrpton, xenon, & radon).

The elements of group 17 (flourine, chlorine, bromine, iodine, and astatine) are known as halogens. The halogens are the most reactive nonmetals They form salts.

A negative ion is known as a anion.

The electrons avaliable to be lost, gained, or shared in formation of chemical compounds are referred to as valence electrons.

• Is a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound.
• Across the Period: Increase. The number of valence electrons increases.
• Down the Group: Decrease. The number of electron shells increase but not the # of valence electrons so there is less attratcive force between the nucleus and valence e-

Accuracy refers to the closeness of a measurment to the correct or accepted value.

Precison refers to the closness of a set of measurements of the same quanity made in the same way.

The mole is the SI unit for an amount of a substance.

Numerical data 25.7g

Non numerical datea such as the fact that the sky is blue.

The mass of one mole of a pure substance is called the molar mass of a substance.

Is the minimum quantity of energy that can be lost or gained by an atom.

Specify the properties of atomic orbitals and the properties of electrons in orbitals.

Attractive force that holds ions together.

An uneven distribution of charge. +/-

even distrubution of charge.

A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of molecules.

Octet rule refers to how elements generally prefer to form bonds so as to attain an octet configuration, i.e. have 8 electrons in their valence shell.

The scientific method is a logical apporach to solving problems that lend themselves to investigation.

• Length-Meters
• Temp.-Kelvin
• Mass-Kilogram
• Time-Seconds
• Mole-Amount of substance
• Ampere-Electric Current
• Candela-Luminous Intensisty

Square Meter (Area); Cubic Meter (Volume).They are produced by dividing or multyplying standard units.

• 1. All matter is composed of extremely small particles called atoms.
• 2. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties. 
• 3.Atoms cannont be subdivided, created, or destroyed. 
• 4. Atoms of different elements combine in simple whole number ratios to form chemical compounds.
• 5. In chemical reactions, atoms are combined, seperated, or rearranged.

Atoms are divisible into even smaller particles (subatomic particles; protons, neutrons, and electrons). Elements can have atoms with different masses.

The cathode ray tube supplied evidence of the existence of electrons, which are negatively charged subatomic particles that have relatively little mass.

Further proved that electrons were negatively charged.

Rutherford found evidence for the existence of the atomic nucleus by bombarding metal foil witha beam of positively charged particles. (He discovered protons).

• Electron / negative
• Neutron / neutral
• Protons / positive

Protons & Neutrons make up the nucleus.

He solved the puzzle of the hydrogen-atom spectrum in 1913. His model linked the atom's electron to photon emission. According to the model, the electron can circle the nuclues in allowed paths or orbits. When the atom is in one of these orbits the atoms has definite energy.

The arrangment of electrons in an atom.

"Father of the Periodic Table;" 1st person to arrange known elements into an orgainzed table.Arranged them by atomic mass w/exceptions, left gaps for undiscovered elements Sc, Ga, Ge, & He.

After the discovery of subatomic particles, Mooseley rearranged the periodic table by atomic number.

• Used to predict the shape of atoms based on the idea that that pairs of valence electrons surronding an atom repel each other.
• Valence
• Shell
• Electron
• Pair
• Repulsion

H bonded with F,O, or N then it has a very strong dipole-dipole bond.

A force of attraction between two molecules with a net dipole.

All molecules/elements.

Matter in the solid state has definte volume and definte shape.

Matter in the liquid state has definte volume but an undefinte shape.

Matter in gas state has neither definite shape or volume.

Plasma is an important fourth state of matter. Plasma is a high temperature physical state of matterin which atoms lose most of their electrons, particles that make up atoms. Plasma is found in fluorescent light bulbs.

Is composed of positive and negative ions that are combined so that the number of positive and negative charges is equal.

The energy released when one mole of an ionic cyrstalline compound is formed from gaseous ions.

The simplest collection of atoms from which an ionic compounds formula can be established. One formula unit of sodium chloride is NaCl.

The forces that hold ionic compounds together have a very strong overall attraction between positive and negative charges. In molecular compounds the covalent bonds are strong ,but not as strong as the formula units in ionic bonding. Ionic compounds generally have higher melting points.

A charged group of covalently charged atoms.

The ability of a substance to be hammered into thin sheets.

Is the study of the composition, structure, and properties of matter, the process matter undergoes, and the energy changes that accompany these processes.

A chemcial is any substance that has a definte composition.

Volume is the amount of three dimensional space an object takes up.

Mass is a measure of the amount of matter.

Is defined as anything that has mass and takea up space.

Depend on the amount of matter present. (Volume, Mass, and Amount of Energy in a Substance)

Do not depend on the amount of substance present. (Melting point, Boiling point, density, and ability to conduct electricity)

Homogenous mixtures are called solutions.

A system is a specific portion of matter in a given region of space that has been selected for study during an experiment or observation.

Explanation of how phenomena occur and how data and events are related.

A broad generalization that explains a body of facts or phenomena.

Something that has magnitude, size, or amount.

A measure of gravitational pull on matter.

When the electron falls to a lower energy level, a photon is emitted, and the process is called emission.

The adding of energy to atoms so they can move bewteen energy levels is called aborsption.

Helium, Neon, Argon, Krypton, Xenon, and Radon.

Alkali metals

Alkaline-earth metals

Transition Metals

Main Group Elements