Answer:
Halogens
Explanation:
From the given choices, the halogens will have the smallest radius within the same period.
The size of an atom is estimated by the atomic radius. This is taken as half of the inter-nuclear distance between two covalently bonded atoms of non-metallic elements or half of the distance between two nuclei in the solid state.
- Across a period in the periodic table, atomic radii decrease progressively from left to right.
- Down a group from top to bottom, atomic radii increase progressively due to the addition of successive shells.
Since halogen is the right most group from the choices given, it will have the smallest radius.
<h3><u>Answer;</u></h3>
A dense substance that is hard and incompressible
<h3><u>Explanation</u>;</h3>
- <em><u>Crystals are solids that are made up of particles such as molecules, atoms or ions, </u></em>which are arrange in a highly ordered microscopic structure, forming a crystal lattice which extends in all directions.
- Examples of crystals include<em><u> quartz,</u></em> that is made up of silicon (iV) oxide molecules that are arranged in a lattice,<u><em>table salt</em></u> is another example that is made up of sodium and chloride ions that are arranged in a lattice
- Crystals are very ordered, they may be made up of atoms of the same elements or atoms of different elements such as in the case of table salt.
Answer:
Extinction event or sometimes known as Mass extinction
Explanation:
These events typically are typically widespread and rapid decrease in the biodiversity (which takes into account spread and existence of current species). The worst mass extinction was Permian–Triassic extinction where over 90% of species of organisms vanished.
Explanation:
The four nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C) and thymine (T).
