matter Flashcards
1
Q
atom
A
the basic unit of matter, physical substance in general.
2
Q
atomic nucleus
A
a collection of protons and neutrons. center of the atom
3
Q
electron cloud
A
the space in which electrons move within the atom. around the nucleus.
4
Q
atomic number
A
the number of protons in the atoms nucleus
5
Q
element
A
a substance that is composed of a single atom.
6
Q
periodic table
A
an organized & convenient reference charts of the elements.
7
Q
period
A
horizontal row on the table of elements.
8
Q
groups or families
A
vertical columns on the table of elements.
