Explanation:
1. Explain how groups 1A-8A in the periodic table are organized by their number of valence electrons.
The valence electrons in an atom are the outermost shell electrons. They are the most loosely held electrons in an atom.
Coincidentally, the periodic table of elements divided into vertical groups and horizontal periods can be said to be arranged according to the number of valence electrons.
- Atomic numbers are used to arrange elements on the periodic table.
- Down a group, the number of electronic shell increases. More electrons are added to new energy levels.
- As we move from left to right across a period, the number of electrons in elements increases but electronic shell is the same.
- Down a group electronic shell increases but the number of valence electrons are the same.
- All elements in Group 1A has just one valence electrons, Group 2A has two valence electrons.........Group 8A has eight valence electrons.
- Moving across groups is synonymous to moving from left to right on the periodic table.
- Due to this trend, the periodic table is arranged based on the number of valence electrons.
3. explain how you know the number of valence electrons for each group.
The number of valence electrons in a group is the group number:
Group Number valence electrons
1A 1
2A 2
3A 3
4A 4
5A 5
6A 6
7A 7
8A 8
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The true statement is (A) energy is absorbed during the reaction
For the products to have more energy, they must absorb it from the surrounding.
Answer:
C.) Alpha, beta, and gamma particles
Explanation:
A dense shield of aluminium can protect Cole from all the listed types of radiation produced from the radioactive particles.
A radioactive protector has very unique and specie ability to contain and prevent the movement of radiations of any types from going into the body.
The strongest and most penetrating radiations are the gamma rays. Any material that can prevent the movement of these rays can halt alpha and beta particles too.
An aluminium shield is made up of multiple layers of aluminium stacked together and it provides enough resistance.
Ba²⁺ + 2Cl⁻ + 2H⁺ + SO₄²⁻ = BaSO₄ (precipitate) + 2H⁺ + 2Cl⁻
Ba²⁺ + SO₄²⁻ = BaSO₄
