Atoms, periodic table, metals, nonmetals, and metalloids

The diagram shows a model of an atom. Atoms contain three different

subatomic particles. Which statement best describes the particle labeled A?

• Particle A exists outside the nucleus.

• Particle A has a negative charge.

• Particle A does not contribute to an atom’s mass

• All of the above are correct.

Which subatomic particles have no electrical charge and may not always be the same in number as the protons? (a)  

• electrons
• neutrons
• atoms
• nucleus

If an oxygen atom has a mass number of 16, how many neutrons are in the atom?

Mathematical Equivalence

ON

In a neutral atom, the number of protons and electrons are as follows:

• more protons than electrons

• equal

• more electron than protons

• none of the above

How many neutrons does sodium have?

• 11

• 12

• 23

• 34

What is the atomic mass of silicon?

• 14

• 15

• 28

• 7

How many protons does calcium have?

• 20

• 21

• 40

• 10

What element is represented in the fourth (bottom) row of the table?

• aluminum

• silicon

• zirconium

• boron

An atom has 18 protons and 8 valence electrons. Which statement would best identify this element?

• The element is highly reactive with eight electrons in its outer shell.

• The element has an atomic mass of 18.

• The element is “happy” or stable because its outer energy level is filled.

• The element is a metal.

Which atom is shiny, has the properties of both metals and nonmetals and has three valence electrons?

• boron

• germanium

• antimony

• tin