Periodic Trends

Elements in group 17 have how many valence electrons?

• 1

• 6

• 7

• 17

Answer explanation

Group 17 = 7 valence electrons

Magnesium lives in Group 2 and has 2 valence electrons. What is the charge of a Magnesium ion?

• +2

• -2

• +4

• +12

Answer explanation

Elements with 1-3 valence electrons lose the electrons.

If an atom loses an electron it becomes a positive ion.

Which element is more metallic? (pink line)

• Boron (B)

• Neon (Ne)

• Francium (Fr)

• Lithium (Li)

Answer explanation

Elements become more metallic as you move down and to the left.

Atoms are happy when they have 8 valence electrons. Nitrogen in column 15 needs to gain how many electrons to be happy?

• 1

• 3

• 5

• 8

This periodic table family is non-reactive (does not react) because it has 8 valence electrons.

• Alkali Metals

• Alkaline Earth Metals

• Halogens

• Noble Gases

Elements in Period 3 have:

• 3 valence electrons

• 3 energy levels

• 3 protons

• 3 nuclei

Answer explanation

Period = horizontal row

Elements in the same period have the same number of energy levels (circles of electrons)

The most reactive nonmetal family

• Alkali metals

• Boron Family

• Halogens

• Noble Gases

Answer explanation

Halogens have 7 valence electrons, so they are very reactive.

Sodium has 1 valence electron. To become an ion it gives away the electron. It now has ____ valence electrons.

• 0

• 1

• 8

• 10

Answer explanation

All ions have 8 valence electrons.

When an energy level (circle) becomes empty, the next circle is the "new" valence electrons.

What is the ionic charge of a Fluorine ion?

• +1

• -1

• +7

• -7

Answer explanation

Fluorine gains 1 electron to become an ion.

Alkali metals are MOST LIKELY to bond with:

• other Alkali metals

• Alkaline earth metals

• Halogens

• Transition metals