Chemistry 2

The smalllest particle of an element that retains the identity of the element

A negatively charges particle within the atom

A particle that is smaller than the atom

In chemistry, the positively charged center of an atom 

A positively charged particle that is part of every atomic nucleus

• An uncharges particle that is part of almost every atomic nucleus
• (the number of neutron in an atom in atomic mass substracted by the atomic number)

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

• The number of protons in the nucleus of an atom
• (22 is the atomic number)

The sum of the number of protons and the number of neutrons in the nucleus of an atom

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 level
• e.g.

The average mass of the naturally occurring isotopes of an element

• A system for organizing the elements into columns and rows, so that 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
• e.g. copper ,silver, gold

• typically, an element that is not shiny, malleable, or ductile and is a poor conductor of heat and electricity
• e.g.Hydrogen, oxygen, carbon

• An element that shares some properties with metals and some properties with non-metals
• e.g. silicon, arsenic

A horizontal row of elements in the periodic table

A vertical column of elements in the periodic table

• Group 1
• have low melting points
• highly reactive

• group 2
• highly reactive(less than alkali metals)
• will burn in air

• Group 17
• Non-metal
• highly reactive
• extremely corrosive

• Group 18
• Non-metal
• colorless
• gas
• non-reactive

An electron in the outermost occupied energy level of an atom