Periodic Table

Mendeleev arranged the known chemical elements in a table according to increasing

• atomic number.

• number of electrons.

• number of protons.

• mass.

Mendeleev gave the name eka-aluminum to a(an)

• compound containing aluminum.

• mixture of aluminum and an unknown element.

• unknown element he predicted would have properties similar to those of aluminum.

• rare isotope of aluminum.

Moving from left to right across a row of the periodic table, which of the following values increases by exactly one from element to element?

• isotope number

• atomic number

• atomic mass unit

• mass number

The standard on which the atomic mass unit is based is the mass of a

• proton.

• neutron.

• chlorine-35 atom.

• carbon-12 atom.

The atomic mass of an element is

• the sum of the protons and neutrons in one atom of the element.

• twice the number of protons in one atom of the element.

• a ratio based on the mass of a carbon-12 atom.

• a weighted average of the masses of the element’s isotopes

At room temperature, none of the metals are

• soft.

• liquids.

• malleable

• gases

Which general statement does NOT apply to metals?

• Most metals are ductile.

• Most metals are malleable

• Most metals are brittle

• Most metals are good conductors of electric current.

Two highly reactive elements in Period 4 are the metal potassium and the

• metalloid arsenic.

• nonmetal selenium.

• nonmetal bromine.

• nonmetal krypton.

Atoms of the most reactive elements tend to have

• one or seven valence electrons

• eight valence electrons.

• four or five valence electrons

• no valence electrons

An alkali metal has one valence electron, while an alkaline earth metal has

• none.

• two.

• four.

• three.