Because atoms are so small, scientists create _____ to describe them.
In an atom, the number of _______ equals the number of electrons.
The ______ move around the nucleus.
The __________ of an element is based on the number of protons.
Electrons have a ______ charge.
Each element is given a specific ________ that usually consists of one or two letters.
The ______ is the very small center core of an atom.
Mendeleev created the first periodic table by arranging elements in order of increasing _______.
scientists who created the first useful periodic table
Scientists now use _______ instead of atomic mass to organize elements in the periodic table.
From an element's location in the periodic table, you can predict its ________.
Elements in the same ______ have similar properties.
A column of elements in the periodic table is called a group, or ______.
The elements in a ____ of the periodic table have properties that change in a pattern.