Why is the atomic mass for calcium a decimal? how many protons does it have? neutrons? electrons?

atomic mass = 40.08 amu

Number of protons = 20

Number of electrons = 20

Number of electrons = 20

Explanation:

The element of group 2A in 4th period is calcium.

Its atomic number is 20.

Its atomic weight is 40.08 amu. The atomic mass is in decimal number because it is the average of isotopes of calcium.

It is third most abundant metal.

It is silvery soft metal.

It react rapidly with water and air.

It is also used as reducing agent.

it is used to make the alloy with copper, aluminium and beryllium.

Its electronic configuration is:

Ca₂₀ = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

1s² 2s² 2p⁶ 3s² 3p⁶ are inner electrons.

4s² are valance electrons. Thus it loses two valance electrons to get complete octet.

Abbreviated electronic configuration:

Ca₂₀ = [Ar] 4s²

the earth would become to overheated and everything alive on it will eventually die from overheating. plants will eventually die as well, water will evaporate, and it will be nothing but a hot planet without anything living on it.

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml