Question

Write a very short note on

1---valancy

2---- AMU

Answer 1

Valency: Atoms are made up of some constituent particles namely protons, nuetrons and electrons. Protons and neutrons are concentrated in side the nucleus while electrons revolves around it. Electrons revolves around nucleus in their respective orbits and orbitals. The valency of an atom is the number of outer most electrons in the outermost orbit. For example: Carbon atom,the atomic number of carbon is 6 and it's electronic configuration is 2,4 this indicates that it's outermost orbit has 4 electrons in spite of this it also indicates the valency of carbon. For metal the valency is from 1 to 3 ,for metalloids it is 4 and for non-metals it is from 5 to 7. This being the most simple explanation for the term Valency. AMU:An atomic mass unit (symbolized AMU or amu) is defined as precisely 1/12 the mass of an atom of carbon-12. The carbon-12 (C-12) atom has six protons and six neutrons in its nucleus.In imprecise terms, one AMU is the average of the proton rest mass and the neutron rest mass. This is approximately 1.67377 x 10^-27 kilogram (kg), or 1.67377 x 10^-24 gram (g). The mass of an atom in AMU is roughly equal to the sum of the number of protons and neutrons in the nucleus.