Atomic number: Number of protons present in the nucleus is called atomic number (Z) of an element. Atomic weight: The sum of mass number of proton and mass number of neutron is called atomic weight or atomic mass number (A). Z = 19 and A = 39 as per atomic weight definition.

Examples. The atomic mass of carbon is 12.011. The atomic mass of hydrogen is 1.0079. The atomic weight of boron samples collected on Earth falls within a range of 10.806 to 10.821.

Atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element’s atoms to some standard. Since 1961 the standard unit of atomic mass has been one-twelfth the mass of an atom of the isotope carbon-12.

The atomic weight of any atom can be found by multiplying the abundance of an isotope of an element by the atomic mass of the element and then adding the results together. This equation can be used with elements with two or more isotopes: Carbon-12: 0.9889 x 12.0000 = 11.8668. Carbon-13: 0.0111 x 13.0034 = 0.1443.

Atomicity is defined as the total number of atoms present in a molecule. For example, each molecule of oxygen (O2) is composed of two oxygen atoms. So atomicity of oxygen is 2.In older contexts, the term atomicity is sometimes used in the same sense as valency.

Atomicity refers to the total number of atoms present in one molecule of an element. For example, argon is a noble gas and exists in a free state. One molecule of argon comprises only one atom. Therefore, the atomicity of argon is one.

Answer Verified. Hint: Atomicity is defined as the total number of atoms present in a molecule. For example in water molecule (H2O) there are 2 atoms of hydrogen ( H ) and one atom of oxygen ( O ) so the atomicity of water molecule (H2O) is 2 + 1 = 3 .

The atomicity of carbon dioxide is 3(1 atom of carbon and 2 atoms of oxygen) and that of water is also 3(2 atoms of hydrogen and 1 atom of oxygen).

Atomicity is the number of atoms of an element present in one molecule of that particular element. Atomicity of phosphorus is 4 as it exist as P4. The number of atoms presents in a molecule of phosphorus are 4 atoms. Was this answer helpful?

7 atoms

6

6 atoms

Percent composition by element

2

Sodium bicarbonate, also commonly known as baking soda, is commonly seen as a white, fine powder and has the chemical formula NaHCO3. It has one sodium atom, one hydrogen atom, one carbon atom, and three oxygen atoms.

36 atoms are represented in Na2​CO3​⋅10H2​O. These include 2 Na atoms, 1 C atom, 13 O atoms and 20 H atoms. Was this answer helpful?

In general, it is pure white dry solid particles having 10 water molecules present as a single unit with sodium carbonate and it is also denoted as Na2CO3.

5 atoms