Weegy: Reading from left to right, they are arranged in increasing atomic number (protons )
Each period (going across) increases in atomic number
As you go down a period, they have one more ring of electrons
As you go down a column, called groups, [ the elements have the same number of valence electrons, which gives them similar chemical activity
Metals are on the left, nonmetals on the right and metalloids along the zig-zag line that divides the metals and nonmetals, inert gases on the far right
In general the elements do get heavier as you increase atomic number, but there are variances ]
User: How do the elements change as you go down a group in the periodic table?
Weegy: There are 118 elements in the periodic table as of Feb 2010
User: Which best describes why scientific models change over time?
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