Chemistry Unit 3

arranged by nuclear charge (# of protons)

Physical and chemical properties of the elements are periodic functions of their atomic numbers

arranged by atomic # and similar properties in groups

shiny metals similar reactivity to group 2

all radioactive, Th –Np naturally occurring, others laboratory created

grouped elements by similar properties, arranged by increasing atomic mass, left spaces for “unknown” elements

regular repeating pattern of properties across a period in the PT

s, f, d, p

alkali metals, alkaline earth metals, hydrogen, helium

silvery appearance, soft, extremely reactive, MP decreases down the group

contain pair of electrons in s sublevel, harder, denser, stronger than alkali metals, very reactive

does not share properties with alkali metals, gas at room temp, flammable

located in group 18, chemically stable, nonreactive

molecules are molecules composed only of two atoms, of either the same or different chemical elements.

groups 13-18,includes metals, nonmetals, and metalloids (not including Helium)

Most reactive nonmetals, react with metals to form salts, F and Cl are gases, Br liquid, I and At solids (F, Br, Cl, I exist as diatomic molecules: F2, Br2, Cl2, I2)

Nonreactive, inert gases

brittle solids, some conductivity of electricity but not as much as metals

harder and denser than s-block, softer and less dense than d-block, stable in presence of air

lanthanides and actinides (inner transition metals)

radius of atom, indicates volume

atomic radii (size) decreases across a period from group 1 to group 18

atomic radii (size) increases down a group from period 1 to period 7

may be defined as one-half the distance between the nuclei of identical atoms that are bonded together.

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

Any process that results in the formation of an ion

The energy required to remove one electron from a neutral atom of an element

The energy change that occurs when an electron is acquired by a neutral atom

Posotive Ion

Negative Ion

The electrons available to be lost, gained, or shared in the formation of chemical compounds

a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound