Chemistry Midterm Review

electronegativity

increases across a period and decreases down a group

hyothesis

An educated guess

polyatomic atom

An ion that is made of more than one atom

Families

Another word for groups, columns of elements on the periodic table

isotope

Atoms of the same element that have different numbers of neutrons. DIffer in mass and physical properties

Which three elements are most likely to form double or triple bonds?

C, N, O

Who conducted the gold foil experiment and what did it prove?

Physicist Ernest Rutherford established the nuclear theory of the atom with his gold-foil experiment. When he shot a beam of alpha particles at a sheet of gold foil, a few of the particles were deflected. He concluded that a tiny, dense nucleus was causing the deflections.

Where are the noble gases located on the periodic table?

They are all the way to the right.

Where are metalloids located on the periodic table?

They border the stair case

Vsepr Theory

Valence-shell electron-pair repulsion theory; because electron pairs repel, molecules adjust their shapes so that valence electron pairs are as far apart as possible

Chemistry

a branch of natural science that deals principally with the properties of substances the changes they undergo and the natural law that describe these changes

precise

a measure of how close a measurement is to the correct or accepted value of the quantity being measured

Homogenous mixture

a mixture in which the composition is uniform throughout

atomic theory

all matter is composed of atoms which are indivisible

Noble Gas characteristics

are odorless, colorless, nonflammable, and monotonic gases that have low chemical reactivity. The full valence electron shells of these atoms make noble gases extremely stable and unlikely to form chemical bonds because they have little tendency to gain or lose electrons

theory

carefully thought out explanation for observations of the natural world that has been constructed using the scientific method,

What experiment led to the discovery of the electron?

cathode ray experiment

What indicates a chemical change?

color change, formation of a precipitate, formation of a gas, odor change, temperature change

volume

cubic meter (m^3)

Example of physical change

cutting, bending, dissolving, freezing, boiling and melting

Ionic Radii

decreases across a period

Atomic Radii

decreases from left to right across a period

extensive property

dependent on the size or amount of sample mass volume lenght

Aufbau Principle

dictates the manner in which electrons are filled in the atomic orbitals of an atom in its ground state.

4th spin (mg)

direction spinning in

1st principle quantum #(n)

distance away from nucleus

most of the volume of atoms is created by

electrons

Hunds Rule

every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.

Halogen Characteristics

form acids when combined with hydrogen, fairly toxic, combine with metals to form salts, seven valence electrons in their outer shell, highly reactive and electronegative

Transitional Metals

good conductors of heat and electricity, hammered or bent into shape easily, high melting points, hard and tough, high densities

Alkali Metals

grou 1, 1 valence electron, +1 charge

Which group of elements is most likely to form two or more ions?

group 16 elements. Their atoms have 6 valence electrons, and need 2 more to have a full valence shell of 8 electrons in order to become stable.

Alkaline Earth Metals

group 2, 2 valence electrons, +2 charge

Halogens

group 7, 7 valence electrons, -1 charge

Noble Gases

group 8, 8 valence electrons, no charge 0

ionic compound characteristics

have very high melting points and boiling points dissolve readily in water and other polar convent and are good conductors of electricity

accurate

how close your measurement is to the correct/accepted value

Why does an electron go from its ground state to its excited state?

if its given extra energy

ionization energy

increases across a period and decreases down a group

intensive property

independent of the amount of substance present density color conductivity

Mass

kilogram (kg)

Where are metals located on the periodic table?

left of staircase

Are most of the elements on the periodic table metals, metalloids, or nonmetals?

metals

Most of the mass of an atom is located in the

nucleus

3rd Magnetic (ml)

orientation in space

Where are the nonmetals on the periodic table?

right of staircase

time

second (s)

2nd Angular Movement (l)

shae

Ionic bond

the electrostatic force that holds oppositely charged particles together in an ionic compound

lattice energy

the energy released when one mole of an ionic crystalline compound is formed from gaseous ions

Alkali Metal characteristics

the high thermal and electrical conductivity, luster, ductility, and malleability that are characteristic of metals. Each alkali metal atom has a single electron in its outermost shell

Periodic Law

the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

frequency

the number of complete wavelengths that pass a point in a given time measured in Hertz (Hz) or 1/sec

atomic number

the number of protons in the nucleus of an atom

Why is an atom electrically neutral?

the number of protons which are positive equal the number of electrons which are negative which cancels out making it neutral.

neutrons

the particles of the nucleus that have no charge

electrical orbital

the path of an electron around the nucleus of an atom

average atomic mass

the weighted average of the atomic masses of the naturally occurring isotopes of an element

Gases

they are easy to compress, (2) they expand to fill their containers, and (3) they occupy far more space than the liquids or solids from which they form.

Alkaline earth metals

two valence electrons. They have low ionization energy, low electron affinity, and low electronegativity. They are highly reactive and often form divalent cations. They are good conductors of electricity. Alkaline earth metals have an oxidation state of +2.

Light has properties of

wave and particles

Covalent Compound characteristics

weak bonds share electrons; can have single, doulbe, or triple bonds poor conductors high volatility no definite pattern of crystalline structure

Anion

A negatively charged ion

first energy level

1 subshel 2 electrons

Law of Conservation of Mass

"The mass in an isolated system can neither be created nor be destroyed but can be transformed from one form to another".

polar covalent bond

A covalent bond in which electrons are not shared equally

d shell

10 electrons fit

f shell

14 electrons fit

s shell

2 electrons fit

Pauli's Exclusion Principle

2 or more identical particles with half-integer spins (no two electrons in the same atom can have identical values for all four of their quantum numbers)

second energy level

3 subshells 6 electrons

3rd energy level

5 subshells 10 electrons

p shell

6 electrons fit

Ion

A charged atom

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Liquids

A liquid has a definite volume and it cannot be compressed. Liquids do not have a definite shape but acquire the shape of the vessel in which it is placed. Liquids can flow from a higher level to lower levels

Heterogenous mixture

A mixture with uneven distribution of different substances, solids, liquids, gases.

cation

A positively charged ion

element

A pure substance made of only one kind of atom

reactants

A starting material in a chemical reaction

compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Density formula

D=m/v

Solid

Definite shape (rigid) Definite volume. Particles vibrate around fixed axes.

valence electrons

Electrons on the outermost energy level of an atom

Which group of elements are the most reactive nonmetals and why?

Halogens because of their valence electrons

Periods

Horizontal rows on the periodic table

What is a physcial change?

In a physical change, the material involved in the change is structurally the same before and after the change.

Chemical Change Example

Iron rusting, wood burning, baking soda and vinegar creating carbon dioxide

Who wrote the atomic theory?

John Dalton

How did Mendeleev and Mosely organize the periodic table

Mendeleev arranged elements ascendingly according to atomic masses, while Moseley arranged them ascendingly according to atomic numbers.

Length

Meter (m)

Electrons

Negatively charged particles outside the nucleus

protons

Positively charged subatomic particles found in the nucleus of an atom

Scientific Method Steps

Question, Research, Hypothesis, Experiment, Analyze the Data, Conclusion

atomic mass

The average mass of all the isotopes of an element

What do the coefficients in a chemical equation represent?

The coefficients indicate the number of each substance involved in the reaction and may be changed in order to balance the equation

wavelength

The distance between two corresponding parts of a wave measured in meters

products

The elements or compounds produced by a chemical reaction.

Milikans experiment

The force on any electric charge in an electric field is equal to the product of the charge and the electric field. Millikan was able to measure both the amount of electric force and magnitude of electric field on the tiny charge of an isolated oil droplet and from the data determine the magnitude of the charge itself.

law of definite proportions

sometimes called Proust's law, or law of constant composition states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation

control

standard for comparison

Law of Multiple Proportions

states that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers