Halogens (atoms with 7 valence electrons) and Hydrogen
or generally, atoms with their shells almost full
atoms are made of 3 types of sub atomic particles; neutrons, protons and electrons
atomic number is the number of protons which is characteristic for the element. Atoms of the same element have the same number of protons.
mass number is the sum of the neutrons and protons.
Isotopes are atoms of the same element with different mass numbers. since they are the same element number of protons are the same but number of neutrons vary.
therefore 2 isotopes are of the same element so they have the same number of protons.
0.115 M means that 0.115 moles of KBr are contained in a volume of 1000 ml, therefore a volume of 350 ml will have (0.115 × 0.35) = 04025 moles
From the formula of molarity moles = molarity × volume in liters
1 mole of KBr is equivalent to 119 g
Therefore, the mass = 0.04025 × 119 g = 4.79 g
Molecule is a chemical substance that cannot be broken down into another chemical substance.
Identical electron configurations : K⁺ and Cl⁻
<h3>Further explanation </h3>
In an atom, there are levels of energy in the shell and sub-shell
This energy level is expressed in the form of electron configurations.
Charging electrons in the sub-shell uses the following sequence:
<em>1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc. </em>
S²⁻ : [Ne] 3s²3p⁶
Cl : [Ne] 3s²3p⁵
K⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶
Cl⁻ : 1s² 2s² 2p⁶ 3s²3p⁶
S :[Ne] 3s²3p⁴
Ar : [Ne] 3s²3p⁶
Cl⁻ : 1s² 2s² 2p⁶ 3s²3p⁶
K : 1s² 2s² 2p⁶ 3s² 3p⁶4s¹
