5 Protons {+}
5 Electrons {-}
6 Neutrons {0}
What element is this ?

boron

Explanation:

The mass number of an atom : a. 11

Further explanation  

The Atomic Number (Z) indicates the number of protons in an atom of an element. If the atom is neutral then the number of protons will be equal to the number of electrons. So the atomic number can also indicate the number of electrons.  

So atomic number = number of protons = number of electrons  

Mass Number (A) is the sum of protons and neutrons  

Mass Number (A) = Number of protons + Number of Neutrons  

So that the relationship between atomic numbers and mass numbers can be formulated as follows:  

Atomic Number (Z) = Mass Number (A) - Number of Neutrons  

An atom has 5 protons, 5 electrons and 6 neutrons

The atomic number = number of protons = number of electrons = 5

The mass number = 5 protons + 6 neutrons = 11

The possible atom in question is Boron (B)

So the  element notation,

Learn more  

The difference between a calcium atom and a calcium ion  

maximum numbers of electrons  

electrons in the highest occupied energy level  

the electron configuration  

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