Answer:
The lowest temperature at which a substance melts
Explanation:
Answer:
10. D
9. A
8. A or B
Explanation:
10. Calcium has 20 electrons, but the Calcium ion has 18 electrons.
9. The mass of electrons are negligible.
8. Electrons have a very small mass where some consider it to have no mass.
Reaction equations contains symbols which show the physical state of the reactants and products.
<h3>What is a chemical equation:</h3>
A chemical equation is an expression that shows the interaction of reactants to yield products. Usually, symbols such as (s), (l), (g), and (aq) are used to show the state of the reactants and products.
The following are the respective meanings of these symbols;
- (s) - solid
- (l) - Liquid
- (g) - gas
- (aq) - dissolved in water
Learn more about reaction equations: brainly.com/question/1170557
Answer:
Pure water has an acidity of about 7 on the pH scale. -is a chemical property of pure water. Pure water has an acidity of about 7 on the pH scale
Answer:
1. hydrogen - H
2. helium - He
3. sodium - Na
4. magnesium - Mg
5. potassium - K
Explanation:
Hydrogen is the element of group 1 and first period. The atomic number of hydrogen is 1 and the symbol of the element is H.
The electronic configuration of the element hydrogen is:-

Helium is the element of group 18 and first period. The atomic number of helium is 2 and the symbol of the element is He.
The electronic configuration of the element helium is:-

Sodium is the element of group 1 and third period. The atomic number of sodium is 11 and the symbol of the element is Na.
The electronic configuration of the element sodium is:-

Magnesium is the element of group 2 and third period. The atomic number of magnesium is 12 and the symbol of the element is Mg.
The electronic configuration of the element magnesium is:-

Potassium is the element of group 1 and forth period. The atomic number of potassium is 19 and the symbol of the element is K.
The electronic configuration of the element potassium is:-
