Question

Help please: Using the periodic table, determine the number of neutrons in 16 O.
a) 4
b) 8
c) 16
d) 24

Answer 1

Number of neutrons equals the number of protons unless it is an isomer.

Answer 2

I thought it was 8 tho?

Answer 3

I am guessing that the 16 is the mass number, which is the sum of protons and neutrons, not the atomic number, which s just the number of protons.

Answer 4

oh, okay. thank you

Answer 5

The mass number i usually written to the left and near the top of the element's symbol.

Answer 6

The atomic number is written to the left, but near the bottom of the symbol.

Answer 7

@joannablackwelder it cant be true
Number of neutrons equals the number of protons unless it is an isomer.
for example u take iron where
26 - atomic no and mass number to be 55.85
no of neutrons = 55.85-26 = 29.85 are the no of neutrons :)
neutrons will be always = mass No - atomic no =
atomic no = no of electrons = no of protons

Answer 8

In my understanding, the number you are referring to as mass number is the relative atomic mass. The mass number is an integral number that is the sum of protons and neutrons in an atom. Since oxygen has 8 protons, that would mean it would have 8 neutrons when the mass number is 16.

Answer 9

In case of Oxygen ur right bcoz it exactly follows what u have said :) but in other cases it wont follow :) u cannot generalize like this
Number of neutrons equals the number of protons unless it is an isomer.