Question

periodic table organization: how are elements arranged in the modern periodic table? what happens to the number of valence electrons as you move from left to right across the periodic table? what is a group? list 3 elements that are in the same group: what do members of a group have in common? what is a period? list 3 elements that are in the same period: what do members of a period have in common?

Explanation:

Elements are arranged by increasing atomic number. Valence electrons increase. A group is a vertical column. Members have same valence - electron number. A period is a horizontal row. Members have same number of electron shells.

Answer:

How are elements arranged in the modern periodic table?: By increasing atomic number
What happens to the number of valence electrons as you move from left to right across the periodic table?: Increases
What is a group?: A vertical column
List 3 elements that are in the same group: Hydrogen, Lithium, Sodium
What do members of a group have in common?: Same number of valence electrons
What is a period?: A horizontal row
List 3 elements that are in the same period: Sodium, Magnesium, Aluminum
What do members of a period have in common?: Same number of electron shells