PLZZ HELP!! An atom has atomic number 11 and mass number 23. How many electrons does the atom have?
23
22
O 12
O 11

12

Explanation:

23-11, why?, because, the difference between atomic and mass number is the neutron number which most a times is equivalent to the electron number.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.