<span>The smallest unit of an element that retains all the characteristics of that element is called an A. atom.
Atoms consist of protons, electrons, and neutrons, but they are particles and don't have the characteristics of the element which is why D is incorrect. B and C are not the smallest units - atoms are smaller than them.
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The metric system is based on powers of 10 so it is much easier to convert units, often just by moving the decimal point.
The atom positions in a general molecule of formula (not shape class) AXn that has shape square pyramidal at the corers of square and one at the above center of the square.
<h3>What is square pyramidal?</h3>
The square pyramidal is a shape geometry of the hybridization in which it consists of one lone pair and 5 bond pairs of electrons that repel each other and due to which the geometry changes from octahedral to square pyramidal.
As atoms are located at the four corners of the planer and one atom at the above center of the planner which is repelled by 4 atoms present at the corner of the planer.
Therefore, the atom positions in a general molecule of formula (not shape class) AXn that has a shape square pyramidal at the corners of the square and one at the above center of the square.
Learn more about square pyramidal, here;
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Unequal heating of the atmosphere
<span>Formula of the 20 common amino acids. The formula of an amino acid comprises, bound to a carbon (alpha carbon): a carboxyl group -COOH. an amine group -NH2.</span>
