120
Average atomic mass of Ca = 40.1 Average atomic mass of O = 16.0 Mr(Ca)/Mr(O) = 40.1/16.0 = 2.51 Thus the calcium atom is about 2.5 times heavier than the oxygen atom.
helium = 4 molar mass
Calcium has 20 electrons and protons; the number of neutrons is specific for each isotope. Number of neutrons in a calcium atom = Mass number - 20
40, the sum of the protons and neutrons.
A mass number is the sum of numbers of protons and neutrons in an atom. Therefore, an element with a mass number of 65 and 36 neutrons contains (65 - 36) or 29 protons and is therefore an atom of copper.
5
18.96 times greater = 19.96 times as great.
The mass of a helium-4 atom is 4,002 602 amu.
A helium-4 atom is just about 1/3 the mass of a carbon-12 atom.
The mass of a helium atom is approximately 4 atomic mass units (amu), which is equivalent to 4.002602 atomic mass units.
The atomic mass of Helium is 4.002602. The atomic mass is the combined number of protons and neutrons in the atom.
Nitrogen is heavier than helium. Nitrogen has an atomic mass of 14, while helium has an atomic mass of 4. This means that nitrogen atoms are approximately 3.5 times heavier than helium atoms.
The lead atom is way heavier than the helium atom. We know this by referring to the Periodic Table of Elements. The atomic mass of lead (Pb) is 207, while that of helium (He) is 4. Therefore, we can estimate that an atom of lead is about 50 times heavier than an atom of helium.
The atomic number of helium is 2. Its mass is 4.002602 u ± 0.000002 u
Isotope.
4.0026 amu
Mass of 1 Helium atom is 4 amu and mass of 1 Carbon atom is 12 amu. So there are 10 helium atoms and 10 carbon atoms