Also, the mass of a proton is assigned 1 atomic mass unit (amu) for convenience. This unit is used for other subatomic particles as well; the mass of electrons in amu (atomic mass units) is 0.00055.

Atomic weight is measured in atomic mass units (amu), also called daltons. See below for a list of chemical elements and their atomic weights. … measured in terms of the atomic mass unit, which is defined to be 1/12 of the mass of an atom of carbon-12, or 1.660538921 × 10−24 gram.

Mass of proton = 1.007277 amu = 1.6726*10-27 kg. Amu stands for atomic mass unit. Obviously, the mass of a proton and neutron are very similar, while the mass of an electron is much less than the other two particles.

: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with the neutron is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673 × 10−27 kilogram.

Lithium

This means that an atom of hydrogen has one proton, and, if it’s neutral, one electron as well….Atomic Number.

lithium atom

Of course, since neutral atoms have to have one electron for every proton, an element’s atomic number also tells you how many electrons are in a neutral atom of that element. For example, hydrogen has an atomic number of 1….Atomic Number.

Be

beryllium

Name Argon

chlorine

calcium

Ar Argon

Atomic Mass of First 30 Elements

Examples

• H – Hydrogen.
• He – Helium.
• Li – Lithium.
• Be – Beryllium.
• B – Boron.
• C – Carbon.
• N – Nitrogen.
• O – Oxygen.

Gold is a metallic element and a transition element having a formula Au. It has the valency of 3 or 1.

Answer. – Silver has electronic configuration [Kr] 4d^10 5s^1. – Usually silver loses one electron from 5s to exhibit valency +1. – At other times, silver loses one electron from 5s & 4d each to show valency +2.

Au

In most case the valency of Ag is 1, as the d sub-shell has stable configuration if they loss 1 electrons from s sub-shell.