Isotopes

Question 1

Define Isotopes

Answer 1

Isotopes are atoms that have the same number of protons but a different number of neutrons. They have the same chemical properties - atomic number (same e- configuration) and different mass numbers.

Question 2

How can isotopes be written?

Answer 2

Isotopes can be written in nuclear notation as element-A.

e.g.: deuterium 2H OR hydrogen-2

Question 3

What does (Ar) mean and its formula?

Answer 3

Relative Atomic Mass (Ar) is a measure of the average mass of an element’s isotopes.

Question 4

What is % abundance?

Answer 4

% Abundance is how much of an element’s isotope exists naturally, shown as a percentage.

Question 5

Why are Atomic Mass not a whole number? Relative Atomic Mass (4 REASONS)?

Answer 5

1. Mass of an atom isn’t simply electron/s + neutron/s + proton/s. 2. Atoms are too small to measure individually. 3. The atomic mass unit (amu) is defined as one-twelfth of the mass of one atom of 12C. 4. Most elements exist as mixtures of several stable isotopes, and the weighted average of the masses of the isotopes is called the atomic mass.

Question 6

What is an atomic mass unit (amu)?

Answer 6

Atomic mass unit (amu) is a standard unit used to measure atomic mass, defined as 1/12th of the mass of one carbon-12 atom.

Question 7

What is the difference between Atomic Mass and Relative Atomic Mass?

Answer 7

Atomic mass is the mass of an atom in amu’s (e.g., Carbon-12 has 12 amu’s), while relative atomic mass is the weighted average of all isotopes based on their abundance.