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Kamila [148]
3 years ago
8

Why atomic mass is an average vàlue​

Chemistry
2 answers:
elena-s [515]3 years ago
7 0

Answer:

There are different isotopes for different elements

Explanation:

The mass of each of the isotopes of an element are added with their percentage each then they are divided by 100

Example boron 11 is 80 % boron 10 is 20%

Total mass of boron 10 is 20*10

Total mass of boron 11 is 80*11

Atomic mass is (20*10)+(80*11)/100

Which is 10.8 and it is rounded off as 11 in the periodic table

lukranit [14]3 years ago
4 0

Answer:

The atomic mass is the average number of protons and neutrons for all natural isotopes of an element. It is a decimal number.

Explanation:

Atomic Mass and Mass Number Example :

Hydrogen has three natural isotopes: 1H, 2H, and 3H. Each isotope has a different mass number.

1H has 1 proton. Its mass number is 1. 2H has 1 proton and 1 neutron. Its mass number is 2. 3H has 1 proton and 2 neutrons. Its mass number is 3. 99.98% of all hydrogen is 1H 0.018% of all hydrogen is 2H 0.002% of all hydrogen is 3H Together, they give a value of atomic mass of hydrogen equal to 1.0079 g/mol.

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Answer:

d) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.

Explanation:

This is an example of a n-type semiconductor. The additional electron introduced to the 'grid' of silicon atoms causes an increase in the conductivity of the silicon. This additional electron is introduced as arsenic loses its extra electron.

5 0
3 years ago
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A reaction that proceeds more slowly than
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Answer: Less energy.
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The maximum amount of nickel(II) cyanide that will dissolve in a 0.220 M nickel(II) nitrate solution is...?
sweet [91]

Answer : The maximum amount of nickel(II) cyanide is 5.84\times 10^{-12}M

Explanation :

The solubility equilibrium reaction will be:

                       Ni(CN)_2\rightleftharpoons Ni^{2+}+2CN^-

Initial conc.                        0.220       0

At eqm.                             (0.220+s)   2s

The expression for solubility constant for this reaction will be,

K_{sp}=[Ni^{2+}][CN^-]^2

Now put all the given values in this expression, we get:

3.0\times 10^{-23}=(0.220+s)\times (2s)^2

s=5.84\times 10^{-12}M

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7 0
2 years ago
Which statement correctly identifies the nuclide that is most likely to be unstable and describes why?
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The answer would be B.

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It is actually the most commonly used isotope is reactors.

C-14 is also a radioactive isotope with 8 neutrons and 6 protons.

The usual and ideal n to p ratio is 1:1 such as C-12 or Mg-24
8 0
3 years ago
What is the valency of aluminium and nitrate in Al (NO3)3​
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Answer:

Aluminum loses three valence shell electrons to become the aluminum ion Al+3. Nitrate is a polyatomic ion with the formula NO3 -1.

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2 years ago
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