Chapter 5 Vocab Chemistry

The Periodic Law

Properties of elements will repeat at regular intervals based on the elements' atomic numbers.

The Periodic Table

an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group.

Alkaline-earth metals:

The elements of Group 2 of the periodic table

Transition elements

The d-block elements are metals with typical metallic properties

Main-group elements:

The p-block elements together with the s-block elements

Halogens

The elements of Group 17

Lanthanides

the first row of the f-block- similar in reactivity to the group 2 alkaline metals

Actinides

the second row of the f-block-are all reactive

Atomic radius

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

Cation

A positive ion

Anion

a negative ion

Ion

an atom or group of bonded atoms that has a positive or negative charge (gains or loses an electron)

Ionization

any process that results in the formation of an ion

Ionization energy(IE)

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

Electron affinity

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

Valence electrons

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

Electronegativity

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

elements arranged in order of increasing atomic mass had similarities in their chemical properties appear at regular intervals

What did Mendeleev notice?

a table in which elements with similar properties were grouped together

What did Mendeleev create?

the elements fit into patterns better when they were arranged according to atomic number

What did Henry Moseley discover?

Atomic Radii

smaller atoms across a period are caused by increasing postive charge of the nucleus. Larger atoms down a group is caused by the increasing size of the electron cloud.

Alkali metals

The elements of Group 1 of the periodic table