Electrons and Periodic Table (copy)

groups

vertical columns of the periodic table; also called families.

electomagnetic radiation

form of energy that exhibits wavelike behavior as it travels through space such as light

periods

horizontal rows of the periodic table.

wavelength

shortest distance between equivalent points on a continuous wave

frequency

the number of waves that pass a given point per second

transition elements

Group B elements on the periodic table that include transition metals and inner transition metals.

metals

Elements that are shiny and are good conductors of heat and electricity.

electromagnectic spectrum

includes all forms of electromagnetic radiation, with the only differences in the types of radiation being their frequencies and wavelengths

alkali metals

Most of group 1. More chemically reactive than alkaline earth metals.

alkaline earth metals

Group 2. Harder and less reactive than alkali metals.

transition metals

elements that form a bridge between the elements on the left and right sides of the periodic table. The elements in groups 3-12 that are contained in the d-block of the periodic table.

nonmetals

These elements are present in every living thing on earth and can form bonds with multiple atoms at once.

halogens

A highly reactive group 17 element.

noble gases

An extremely unreactive group 18 ele- ment.

metalloids

share the same physical and chemical properties of both metals and nonmetals. silicon and germanium are the most important.

valence electrons

electrons on the outermost principal energy level of an atom.

Relationship between valence electrons and period

the energy level of the valence electrons of an element indicates the period on the periodic table in which it is found.

Relationship between valence electrons and group number

the group number of a representative element is the same as its number of valence electrons. But, there are many exceptions.

atomic radius for metals

half the distance between adjacent nuclei in a crystal of the element.

atomic orbital

wave function predicts a three-dimensional region around the nucleus

atomic radius for nonmetals

half the distance between nuclei of identical atoms that are chemically bonded together.

electron configuration

the arrangement of electrons in an atom

ion

an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge.

aufbau principle

states that each electron occupies the lowest energy orbital available

ionic radius

the distance from the nucleus to the outer energy level of the ion.

Pauli exclusion principle

states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins

ionization energy

The amount of energy required to remove an electron from an atom.

Hund's rule

states the single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

electronegativity

The tendency of an atom to attract electrons in the formation of an ionic bond.

valence electron

are defined as electrons in the atom's outermost orbitals - generally those orbitals associated with the atom's highest principal energy level

atomic radius trends

increases as you move down groups. decreases as you move right across periods.

electron-dot structure

consists of the element's symbol, which represents the atomic nucleus and inner-level electrons, surrounded by dots represnenting all of the atom's valence electrons

electronegativity trends

decreases as you move down groups. increases as you move right across periods. not ionization.

ionization energy trends

decreases as you move down groups. increases as you move right across periods. not electronegativity.

octet rule

atoms will gain, share, or give up electrons to achieve the electron configuration of a noble gas. meaning 8 valence electrons.

periodic law

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

Mendeleev

Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements (1834-1907). Arranged the table in increasing mass

Moseley

Arranged the periodic table according to atomic number instead of mass