Why is the atomic weight of oxygen 16?

Atomic mass of an element is the relative mass of its atom as compared with the mass of a carbon-12 atom taken as 12 units. Hence, atomic mass of oxygen is 16 u means that one atom of oxygen is 16 times heavier than 1/12 of a carbon-12 atom.

What does the 15.999 in oxygen mean?

Correct! Oxygen is a non-metal with an atomic mass of 15.999. Oxygen’s atomic number is 8. It is a colorless, tasteless and odorless element that consitutes 21\% of the atmosphere. Oxygen is a non-metal which means that it is not easily able to conduct electricty or heat and does not reflect light.

What does 15.999 mean?

An oxygen atom usually has 8 protons, 8 neutrons, and 8 electrons. Looking at the periodic table, oxygen has atomic number 8 and atomic weight 15.999. The atomic number tells you how many protons are in the atom’s nucleus. This identifies the atom.

Why is the atomic mass of oxygen?

Atomic and Molecular Weights Hydrogen, the lightest element, was assigned a relative mass of ‘1’, and the other elements were assigned ‘atomic masses’ relative to this value for hydrogen. Thus, oxygen was assigned an atomic mass of 16.

Why did carbon 12 replace oxygen 16?

Answer Expert Verified Earlier Oxygen was used as the reference for mass measurements. Carbon was being increasingly used as a reference in mass spectroscopy. Choosing pure C-12 isotope as the reference made the changes in the masses of elements and compounds to be small. Choosing oxygen needed making bigger changes.

What is atomic weight of oxygen?

15.999 u
Oxygen/Atomic mass
Another example: oxygen exists as a mixture that is 99.759\% 16O, 0.037\% 17O and 0.204\% 18O. The atomic mass of oxygen (use percent natural abundance data from Table 2.5.1) would be calculated as follows: Atomic mass = (\%1)(mass 1) + (\%2)(mass 2) + (\%3)(mass 3) 0.99759(15.995u)+0.00037(16.995u)+0.00204(17.999u)=15.999u.

What series is plutonium in?

actinoid series
plutonium (Pu), radioactive chemical element of the actinoid series of the periodic table, atomic number 94.

How do you find the atomic weight of oxygen?

How to Find Atomic Mass?

1. Example: Calculation of the atomic mass of an oxygen molecule with 9 neutrons.
2. Step 1: Multiply the atomic mass of the isotope with its abundance percentage and divide the result by 100.
3. Step 2: Add the values gained from step 1 for each given isotope in the sample.

What is the relative atomic mass of oxygen 15?

The relative atomic mass of oxygen is 15.9994. Why is the relative atomic mass of oxygen less than 16? The atomic mass of an element is defined as the average of the isotopic masses, weighted according to the naturally occurring abundances of the isotopes of the element.

How many protons and neutrons does oxygen 18 have?

Oxygen 17 contains 8 protons and 9 neutrons, for an atomic mass of 17, and Oxygen 18 contains 8 protons and 10 neutrons, for an atomic mass of 18. If all (100\%) oxygen atoms were Oxygen… Oxygen has 3 different stable isotopes.

How many isotopes of oxygen are there?

Although oxygen has nine isotopes with mass numbers ranging from 13 to 21, oxygen-13, oxygen-14 and oxygen-15 are not naturally occurring isotopes. So, we do not need to include them when we calculate the relative atomic mass of oxygen.

Why is the mass of one carbon-12 atom a whole number?

It is important to note that only the mass of one carbon-12 atom is a whole number because, by international agreement, one atom of the carbon-12 isotope has been assigned a mass of 12 atomic mass units. The concept of isotopic mass is not clearly described in many textbooks.