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)

They have different mass numbers
- different physical properties derived from mass

Question 2

How can isotopes be written?

Answer 2

Nuclear notation and may be written as element-A.

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

Question 3

What does (Ar) mean and its formula?

Answer 3

Relative Atomic Mass and:

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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)? (CHANGE ASK MRS)

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. Atomic mass isn’t a whole number because it’s a weighted average of isotopes based on their abundance. The amu is ¹/₁₂ of a ¹²C atom’s mass.
4. Atomic mass is the weighted average of an element’s stable isotopes.

Question 6

What is an atomic mass unit (amu)?

Answer 6

Atomic mass unit (amu) is a standard unit used to measure atomic mass. It is defined as 1/12th of the mass of one carbon-12 atom. This gives a consistent reference for comparing the masses of different atoms.

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 (Carbon-12 has 12 amu’s). While relative atomic mass is the weighted avg of all isotopes based on their abundance.