Lawhunter220

Atomic Mass of Silicon. Atomic mass of Silicon is 28.0855 u. The atomic mass is the mass of an atom. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element.

• Atomic Mass and Atomic Number Worksheet - Key Name of Element Symbol Atomic. Silicon Si 14 28 14 14 14 chlorine Cl 17 35 17 18 17 bismuth Bi 83 209 83 126 83.
• Silicon Uses - Silicon (Si) is a close relative of carbon in the periodic table with atomic number 14. Silicon is used in semiconductor industries for manufacturing microelectronics devices. Know the Silicon Atomic Number, Silicon Properties, Atomic Mass, and more at BYJU'S.

What is the average atomic mass of silicon?

Given the following data, calculate the average atomic mass of silicon.

isotope = Si-28
amu =27.9769
abundance(%) =92.18

isotope = Si-29
amu =28.9765
abundance(%) =4.71

isotope =Si-30
amu =29.9738
abundance(%) =3.12

1 Answer

Multiply the amu by the percentage of occurrence to arrive at an average atomic mass of #28.0891#

Explanation:

Silicon Atomic Mass Rounded

We take the amu of each isotope, multiply it by the percentage of occurrence, and end up with a weighted average:

#27.9769xx.9218+28.9765xx.0471+29.9738xx.0312# (quick note - there is a bit of rounding in here - the abundance percentages add up to 1.01, so the number we calculate is going to be slightly off).

This simplifies to:

#25.7891+1.3648+0.9352=28.0891#

Checking 'the internet' to verify our answer, I found 28.0855 u ± 0.0003 u, so the answer calculated for our question is pretty close.

Related questions

The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope. (Atomic mass is also referred to as atomic weight, but the term 'mass' is more accurate.)

For instance, it can be determined experimentally that neon consists of three isotopes: neon-20 (with 10 protons and 10 neutrons in its nucleus) with a mass of 19.992 amu and an abundance of 90.48%, neon-21 (with 10 protons and 11 neutrons) with a mass of 20.994 amu and an abundance of 0.27%, and neon-22 (with 10 protons and 12 neutrons) with a mass of 21.991 amu and an abundance of 9.25%. The average atomic mass of neon is thus:

Silicon Atomic Mass And Atomic Number

The atomic mass is useful in chemistry when it is paired with the mole concept: the atomic mass of an element, measured in amu, is the same as the mass in grams of one mole of an element. Thus, since the atomic mass of iron is 55.847 amu, one mole of iron atoms would weigh 55.847 grams. The same concept can be extended to ionic compounds and molecules. One formula unit of sodium chloride (NaCl) would weigh 58.44 amu (22.98977 amu for Na + 35.453 amu for Cl), so a mole of sodium chloride would weigh 58.44 grams. One molecule of water (H₂O) would weigh 18.02 amu (2×1.00797 amu for H + 15.9994 amu for O), and a mole of water molecules would weigh 18.02 grams.

The original periodic table of the elements published by Dimitri Mendeleev in 1869 arranged the elements that were known at the time in order of increasing atomic weight, since this was prior to the discovery of the nucleus and the interior structure of the atom. The modern periodic table is arranged in order of increasing atomic number instead.