periodic

Choose the correct answer using the periodic table for the element O.

• Na and Cl

• Na and Ca

Type the correct answer using the periodic table for the element O:

What is its atomic number?

Select the best answer.

• element

• electron dot

• Bohr

• Linnaeus

Select the best answer. Sulfur can form ions with a -2 charge. Is it a cation or an anion?

• anion

• neither

• cation

Select the best answer. Why do atoms want 8 valence electrons?

• 8 valence electrons is a full shell which makes the atom more stable.

• 8 valence electrons helps atoms dissolve in water.

• In nature, 8 is the number at which all matter is most happy.

• 8 valence electrons make the atom better able to react with other elements.

Choose the correct answer using the periodic table for the element O. Which of these elements has a higher electronegativity?

• Li

• Cs

Select the best answer. Looking at the diagram, how many valence electrons does N have?

• 5

• 3

• 1

• 2

Select the best answer. ____________________ are the most reactive nonmetal group.

• Halogens

• Noble gases

• Metalloids

• Atomic masses

Select the best answer. Elements that are dull, brittle, often are gases at room temperature, and do not conduct heat and electricity well are________________________.

• halogens

• nonmetals

• metals

• metalloids