Periodic Table Trends

In the periodic table hydrogen is placed in Group 1A and helium is placed in Group 8A. The most likely reason for this is: 

• Hydrogen has one outer shell electron and helium has a full outer shell of electrons.

• Hydrogen has one outer shell electron and helium has 8 electrons in its outer shell.

• Hydrogen and helium are both metals.

• Hydrogen and helium are both gases.

Which statements are true concerning elements in the same group of the periodic table? 

• They have similar periodic properties and the same outer shell electron configuration.

• They are all metals or nonmetals, but not both.

• They are either all solids or all liquids or all gases.

• They have the same number of shells of electrons.

Lithium is in Group 1A, Period 2 of the periodic table. Which statement describes the charge of the ion it typically forms?

• It forms a cation with +2 charge.

• It forms a cation with a +1 charge

• It forms an anion with a +1 charge.

• It forms an anion with a −1 charge.

The elements K, Ca, Se+, Kr, and Ga− all appear in Period 4 of the Periodic Table.  Which arrangement, from left to right, orders them with respect to their atomic size, from largest to smallest?

• K; Ca; Se+; Kr; Ga

• Ca; Ga; K, Kr; Se

• K; Kr; Se; Ca; Ga

• K; Ca; Ga; Se; Kr

Which arrangement of the following Period 5 elements, from left to right, orders them with respect to their atomic size, from smallest to largest?

• Rb; Sr; In; Sb; Te

• In; Rb; Sb; Sr; Te

• Te; Sb; In; Sr; Rb

• In; Sb; Te; Rb; Sr

Which characteristic is not a periodic trend?

• atomic radius

• electron affinity

• ionization energies

• number of elements in a group

Which pair of words correctly completes the statement?

Alkali metals are highly ___ since they ___ easily to form ions.

• nonreactive; lose 1 electron

• nonreactive; lose 2 electrons

• reactive; lose 1 electron

• reactive; gain 1 electron

On the periodic table, Periods are

• Horizontal rows

• Vertical columns

What's a valence electron?

• electrons in the second energy level
• electrons in the outermost energy level
• the atomic number
• electrons in the first level

What is the mass number of this atom?

• 1
• 3
• 4
• 7