The atomic number, z, is the number of protons. Assuming that this is an electrically neutral atom -the number of protons equals the number of electrons-, we can say that the atomic number is 4.
----------------------------------------
The representation of an element includes a superior number that indicates the massic number, and an inferior number that indicates the atomic number. We need to know that every atom is identified by its number of protons and neutrons. So,
Representation ⇒ ᵃ X ₀
Where
• X is the element
• a is representing the massic number, which is defined as the sum of the number of protons and the number of neutrons.
• z is the atomic number, which is the number of protons ⇒ represented as
0 above
In electrically neutral atoms, the number of protons equals the number of electrons. This means that the atomic number also indicates the number of electrons.
• We will call n to the number of neutrons, which equals a - z
When protons, neutrons, and electrons get together to form an atom, they lose part of their mass as energy. This is why the atomic weight is slightly inferior to the sum of masses.
So, what you need to know is that
• Nº of protons = Atomic number → z
• Nº of neutrons = Massic number - Atomic number → n = a - z
• Nº of Electrons = Nº of protons = Atomic number → z
Let us analyze the carbon example.
Element representation ⇒ ¹⁴ C ₆
• Massic number = 14
• Atomic number = 6
So, from this information we can assume that
• Nº of protons = Atomic number → 6
• Nº of neutrons = Massic number - Atomic number → 14 - 6 = 8
• Nº of Electrons = Nº of protons = Atomic number → 6
In the exposed example, we have an element, let us name it X with 5 netrons and 4 electrons. And we need to say what is the atomic number, z. In this example we do not need to do perform any calculations, because we already know that the atomic number = number of protons = number of electrons, so
• Nº of neutrons = Massic number - Atomic number → 5
• Nº of Electrons = Nº of protons = Atomic number → 4
from this information we can assume that the massic number is 9, because the massic number = number of protons + number of neutrons.
---------------------------------
Related link: https://brainly.com/question/17274608?referrer=searchResults
