Atoms of elements that are in the same group have the same number of

• protons.

• neutrons.

• valence electrons.

• protons and neutrons.

Which of the following elements is an alkali metal?

• calcium

• magnesium

• mercury

• sodium

In Mendeleev's periodic table, elements in each column had similar

• atomic masses.

• properties.

• atomic numbers.

• symbols.

Each column of the periodic table is

• an element.

• a group.

• an isotope.

• a period.

The order of elements in the modern periodic table is based on an element's

• atomic number

• proton number

• chemical symbol

• atomic mass

Which statement about the alkali metals is correct?

• They are located in the left-most column of the periodic table.

• They are extremely nonreactive.

• They are usually gases.

• They form negative ions with a 1- charge.

Metals tend to be

• gases.

• dull.

• brittle.

• good conductors.

Which group is very stable due to the fact that they have a full outermost energy level?

• alkali metals

• halogens

• alkaline-earth metals

• noble gases

Which of the following is a property of group 18 elements?

• malleable

• brittleness

• high electrical conductivity

• unlikely to react with other elements

Based on its location on the periodic table, which of these elements most likely has physical and chemical properties most similar to boron (B)?

• magnesium (Mg)

• aluminum (Al)

• neon (Ne)

• chlorine (Cl)