Answer:1:En química, el número másico o número de masa es la suma del número de protones y el número de neutrones del núcleo de un átomo. Se simboliza con la letra A (el uso de esta letra proviene de alemán Atomgewicht, que quiere decir peso atómico, aunque sean conceptos distintos que no deben confundirse).
2:
Theodore Richards; first scienstist to recieve nobel prize in Chemistry, earning the award "in recognition of his exact determinations of atomic weights of a large number of chemical elements."
There are 424 pints in <span>53 gallons.</span>
Principal quantum number is n = 2, principal quantum number gives the energy shells electrons reside in,
angular momentum quantum number , these are the number of subshells and gives how many subshells are there in energy shells, values for l range from 0 to n-1
magnetic quantum number -m- gives the specific orbital in the subshells and their orientation.
spin quantum number gives the spin of the electrons.
in this case, n = 2
the types of subshells in n=2 are 0 and 1
0 - s subshell
1 - p subshell
the specific number of orbitals are given by -l to +l
when l = 1
then -1, 0 and +1
therefore there are 3 orbitals in p subshell and orbitals are in 3 orientations
each orbital can hold a maximum of 2 electrons,
since there are 3 orbitals each holding 6, there are 6 electrons to which these quantum numbers are the same
answer is 6
