Complete the sentence to explain why the atomic weight of carbon is reported as 12.011 in the table of elements and the periodic table in the front inside cover of the textbook.

The average mass of a carbon atom 12.011, is the average of the masses of all the isotopes ¹²C and ¹³C

The elements in nature have several types of isotopes

Isotopes are atoms whose atomic number has the same number of protons while still having a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

Atomic mass is the average atomic mass of all its isotopes

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu

So the atomic mass is obtained is the mass of the atom relative to the 12th carbon atom

An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.

The 'amu' unit has now been replaced with a unit of 'u' only

The natural abundance of ¹⁴C, ¹⁰C and ¹¹C is so small that we use the isotopes of ¹²C and ¹³C to calculate the average mass of a carbon atom

The average atomic mass is the average of the masses of all

the isotopes

Average atomic mass X = mass isotope 1. % + isotope mass 2.%

The natural abundance of ¹³C is 1.11%, and the natural abundance of ¹²C is 98.89%

The mass of ¹²C is 12 amu.

the mass of ¹³C is 13.003355 amu

so that:

average atomic mass C = (0.9889 x 12 amu) + (0.0111 x 13.00335 amu)

 = 11.8668 + 0.1443

 = 12,011 amu

element  X  

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the chemical symbols

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two stable isotopes of bromine

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Keywords : the isotope, C, atomic number , mass number

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

gold is my favorite solid.