ON Science 9:Chapter 5

The smallest particle of an element that retains the identity of the element. 

A negatively charged particle within the atom.

A particle that is smaller than the atom.

In chemistry, the positively charged centre of an atom.

A positively charged particle within the atom.

An uncharged particle that is part of almost every atomic nucleus.

A possible level of energy an electron can have in an atom.

The number of protons in the nucleus of an atom.

The average mass of the naturally occurring isotopes of an element.

One of two or more forms of an element that have the same number of protons but a different number of neutrons.

A model of the atom in which a central positive nucleus is surrounded by electrons in energy levels.

The average mass of the naturally occurring isotopes of an element.

A system for organizing the elements into columns and rows, so the elements with similar properties are in the same column.

Typically, an element that is hard, shiny, malleable and ductile, and is a good conductor of heat and electricity.

Typically, an element that is not shiny, malleable, or ductile, and is a poor conductor of heat and electricity.

An element that shares some properties with metals and some properties with non-metals.

A horizontal row of elements in the periodic table.

A vertical column of elements in the periodic table.

Any of a group of soft, white, low density, highly reactive metallic elements. Eg. Lithium, sodium, potassium.

Any of the bivalent metals of group II of the periodic table. Eg. Calcium,strontium,barium,magnesium.

Any of the elements fluorine, chlorine, bromine, iodine, and astatine, occupying group 17 of the periodic table.

Any of the gaseous elements helium, neon, argon, krypton, xenon, and radon, occupying Group 18 of the periodic table

An electron in the outermost occupied energy level of an atom.