Atom's Quiz

How are ions alike? How are they different?

alike - same # of protons; different - different # of electrons

What one number identifies an atom?

atomic number

What is an ion?

atoms of the same element that have a charge (+ or -)

What is an isotope?

atoms of the same element that have different masses (because they have different numbers of protons and neutrons).

What does the average atomic mass of an element depend upon?

the relative abundance of the isotopes

An atom has no net electrical charge because

•the positively charged protons cancel out the negatively charged electrons

What is the atomic number equal to?

# of protons

What is the mass number equal to?

# of protons and neutrons

The number of protons in an atom of 3^1H is

1

Explain how an ion would have a negative charge. Explain how it would have a positive charge.

A negative charge comes from an atom "gaining" electrons. A positive charge comes from at atom "losing" electrons. (Electrons have a negative charge and are equal to the number of protons (positive) in a neutral atom. Having more electrons results in the overall charge becoming negative and having less electrons results in the overall charge becoming positive.)

How is atomic mass calculated?

First the percent (or fractional or relative) abundance of each isotope is found. The fractional abundance is then multiplied by the average atomic mass of that isotope, and repeated for each isotope. The sum of these calculations is equal to the atomic mass of the element.

Using the periodic table, find the number of protons (p), neutrons (n), and electrons (e) for the following: a) Si-28 b) Si-30 c) Ca2+ d) P3-

a) p-14 n-14 e-14 b) p-14 n-16 e-14 c) p-20 n-20 e-18 d) p-15 n-17 e-18

How are the isotopes of a particular element alike? How are the different?

alike - same # of protons different - different # of neutrons