atomic mass

What is the approximate mass of one proton in atomic mass units (amu)?

Approximately 1 amu

How is the atomic mass unit (amu) defined?

As exactly 1/12 the mass of the carbon-12 atom, approximately 1.66 × 10−24 g

What does the atomic mass of an atom in amu represent?

It is nearly equal to its mass number, the sum of protons and neutrons.

What are isotopes?

Atoms of the same element with varying mass numbers, differing in their number of neutrons.

How are isotopes named?

By the name of the element followed by the mass number, e.g., carbon-12 or iodine-131.

What are the unique names for the three isotopes of hydrogen?

Protium (1 proton, 1 amu), Deuterium (1 proton, 1 neutron, 2 amu), Tritium (1 proton, 2 neutrons, 3 amu).

Why do isotopes generally exhibit similar chemical properties?

Because they have the same number of protons and electrons.

What is atomic weight?

The weighted average of the different isotopes of an element, reported on the periodic table.

Why is chlorine's atomic weight closer to 35 than 37?

Because chlorine-35 is about three times more abundant than chlorine-37.

What does it mean when an element has two or more isotopes?

No one isotope will have a mass exactly equal to the element's atomic weight.

What is the atomic weight of bromine listed as?

79.9 amu, which is an average of bromine-79 and bromine-81.

What does the atomic weight represent?

The mass of the average atom of that element in amu and the mass of one mole of the element in grams.

What is Avogadro's number?

NA = 6.02 × 10^23, representing the number of atoms in one mole.

If the atomic weight of carbon is 12.0 amu, what does this imply?

The average carbon atom has a mass of 12.0 amu, and 6.02 × 10^23 carbon atoms have a combined mass of 12.0 grams.

How do you calculate the atomic weight of an element with multiple isotopes?

By taking the weighted average of the isotopes based on their abundance.

In the example of element Q, what is the atomic weight if Isotope A has 40 amu and accounts for 60%?

0.60 (40 amu) + 0.25 (44 amu) + 0.15 (41 amu) = 41.15 amu.

What is the mass of an electron compared to protons and neutrons?

The difference in mass between protons and neutrons is extremely small and is approximately equal to the mass of an electron.

What is the significance of binding energy in atomic mass?

Some mass is lost as binding energy, affecting the total mass of protons and neutrons.

What is the relationship between atomic mass and mass number?

Atomic mass is nearly synonymous with mass number.

What is a mnemonic to remember the difference between atomic mass and atomic weight?

Atomic mass is nearly synonymous with mass number; atomic weight is a weighted average of isotopes.