name= calcium
atomic mass= 40.078 atomic mass unit
no of protons= 20
no of electrons=20
Answer: 
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here iron is having an oxidation state of +3 called as
cation and oxide
is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral
.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

Answer:
<h3>25.0 grams is the mass of the steel bar.</h3>
Explanation:
Heat gained by steel bar will be equal to heat lost by the water

Mass of steel=
Specific heat capacity of steel =
Initial temperature of the steel = 
Final temperature of the steel = 

Mass of water= 
Specific heat capacity of water=
Initial temperature of the water = 
Final temperature of water = 

On substituting all values:

<h3>25.0 grams is the mass of the steel bar.</h3>
A beta emission radioactive decay can pass through the body.
Answer:
This is all true if the atom has to be neutral.
Also what does V mean?
Helium: one shell with 2 neutrons and 2 protons in the center, with 2 electrons in the first shell.
Lithium: two shells with 4 neutrons and 3 protons in the center, with 2 electrons in the first shell, and 1 electron in the second shell.
Nitrogen: two shells with 7 neutrons and 7 protons in the center, with 2 electrons in the first shell, and 5 electrons in the second shell.
Flourine: two shells with 9 protons and 10 neutrons in the center, with 2 electrons in the first shell, and 7 electrons in the second shell.
Neon: two shells with 10 neutrons and 10 protons in the center, with 2 electrons in the first shell, and 8 electrons in the second shell.
Boron: two shells with 6 neutrons and 5 protons in the center, with 2 electrons in the first shell, and 3 electrons in the second shell.