20 terms

Science 9 Chemistry Section 2

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metal
group of elements that are shiny, ductile and conduct electricity
non-metal
a group of elements that are dull, non-malleable, and good insulators
metalloid
a group of elements that have some properties of metals and some properties of non-metals
Atomic number
this number is equal to the number of protons in the nucleus of a particular element
Atomic mass
the mass of one atom of an element; also equal to the sum of the protons and neutrons in an element
group/family
a vertical column in the periodic table; elements have similar properties
period
a horizontal row in the periodic table
halogen
the most reactive group of non-metals
Noble gas
very unreactive non-metals
Alkali metal
the most reactive group of metals
Alkaline earth metal
group two metals; have the second highest reactivity of the metals
proton
positively charged particle found in the nucleus of the atom
electron
negatively charged particle in the atom that orbits the nucleus
neutron
heavy subatomic particle with no charge
Quantum mechanics model
The atom has a nucleus in the center (with protons and neutrons) and a cloud of electrons around the nucleus
Nagaoka and Rutherford
The atom is made up of mostly empty space with electrons circling far away from a nucleus
J.J. Thomson
The atom is like a raisin bun with positive and negative charges
John Dalton
The atom is like a billiard ball and cannot be divided into smaller pieces
Neils Bohr
The atom has electron shells
Chadwick
Nucleus contains positively charged particles called protons and neutral particles called neutron