Question

The atomic number of an element having mass number 23 and number of neutron 12 is- fill in the blanks.

Answer 1

Hint: Before answering this question, we should know that:
Atomic Number (Z) = Number of electrons = Number of protons.
Mass number = no. of protons + no. of neutrons, Now with the help of this formula we can easily solve the question.

Complete answer:
Atomic number
The atomic number is given by the total number of protons present in the nucleus of an atom. It is represented by Z. The element has atoms which consist of the same number of protons and have the same atomic number. Different elements have atoms which have the same atomic number. For example: The atomic number of carbon is 6 whereas the atomic number of oxygen is 8.
Mass number
Mass number of an atom is a combination of the number of protons and neutrons. It is represented by A. Nucleons is the term used to represent both protons and neutrons. Carbon has 6 protons and 6 neutrons, The mass number of it is 12. The number of neutrons can vary whereas the number of protons remains the same. The weight of an electron is equal to 0 which makes the atomic mass of an atom the same as the mass number. Atoms that are of the same element can have a different number of electrons which are called ions and a different number of neutrons that are isotopes.
Mass number = 23
Number of neutrons = 12
Number of protons = 23-12
                                    = 11

Note:
The outermost subatomic particle of an atom is known as an electron. These electrons are negatively charged in nature and they revolve around the nucleus in an atomic orbit. These outer electrons are also termed as valence electrons of an element. Now, looking into the inner side of the nucleus where most of an element lies, that is protons and neutrons. Protons are stable and positively charged subatomic particles whereas neutrons possess neutral charge. Protons and neutrons have almost the same mass i.e $1.67\times {{10}^{-24}}$grams whereas electrons have much lesser mass compared to protons and neutrons i.e $9.1\times {{10}^{-28}}$.