Atomic Structure and Chemical Bonding
Structure of an atom, mass, number and atomic number, isotopes and octet Rule.
Answers
Answer:
Explanation:
Atomic Number :-
Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged). Atoms have different properties based on the arrangement and number of their basic particles.
The hydrogen atom (H) contains only one proton, one electron, and no neutrons. This can be determined using the atomic number and the mass number of the element (see the concept on atomic numbers and mass numbers).
Atomic Mass :-
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams. Scientists define this amount of mass as one atomic mass unit (amu) or one Dalton. Although similar in mass, protons are positively charged, while neutrons have no charge. Therefore, the number of neutrons in an atom contributes significantly to its mass, but not to its charge.
Electrons are much smaller in mass than protons, weighing only 9.11 × 10-28 grams, or about 1/1800 of an atomic mass unit. Therefore, they do not contribute much to an element’s overall atomic mass. When considering atomic mass, it is customary to ignore the mass of any electrons and calculate the atom’s mass based on the number of protons and neutrons alone.
Electrons contribute greatly to the atom’s charge, as each electron has a negative charge equal to the positive charge of a proton. Scientists define these charges as “+1” and “-1. ” In an uncharged, neutral atom, the number of electrons orbiting the nucleus is equal to the number of protons inside the nucleus. In these atoms, the positive and negative charges cancel each other out, leading to an atom with no net charge.
Isotopes :-
Isotopes are various forms of an element that have the same number of protons, but a different number of neutrons
Octet Rule :-
The octet rule refers to an important principle that the atoms which have bonded share eight outer electrons. This certainly means that the atom’s valence shell has a resemblance with a noble gas.
The octet rule states that the atoms like to have eight electrons only in their full outer shells. For achieving eight electrons in their outer shells, atoms would gain or lose the valence electrons.
Furthermore, the atom does this by bonding with each other. Moreover, these atoms can be the same element or with different elements.
Two notable exceptions to the octet rule are helium and hydrogen. This is because both are happy with two electrons belonging in the outer shells.