The symbol of an atom is X. Its nucleus contains 29 protons and 34 neutrons. Write its (a) mass number, (b) atomic number, (c) number of electrons, (d) write symbol of its nuclide.​

An element has 5 protons and 6 neutrons in its nucleus. Calculate (a) number of electrons, (b) atomic number,(c ) mass number,(d) valence electrons, (e) valency.

An atom of element E contains 3 protons, 3 electrons and 4 neutrons:
(a) What is its atomic number?
(b) What is its mass number?
(c) Write the electronic configuration of the element E.
(d) State whether element E is a metal or non-metal. Why?
(e) What type of ion, cation or anion, will be formed by an atom of element E? Why?
(f) Write the symbol of the ion formed by an atom of element E.
(g) What could element E be?

Fill in the blanks in the following statements :

(a) The number of protons in the nucleus of an atom is called its ....................

(b) The total number of protons and neutrons in the nucleus of an atom is called its ....................

(c) An atom has atomic mass number 23 and atomic number 11. The atom has .................... electrons.

(d) An atom of an element has 11 protons, 11 electrons and 12 neutrons. The atomic mass of the atom is ....................

(e) If the nucleus of an atom has atomic number 17, mass number 37 and there are 17 electrons outside the nucleus, the number of neutrons in it is ....................

(f) Almost all the mass of an atom is concentrated in a small region of space called the ....................

(g) Cathode rays are a beam of fast moving ....................

(h) The anode rays obtained from hydrogen gas consist of particles called ....................

(i) The maximum number of electrons that can be accommodated in L shell are ....................

(j) The maximum number of electrons that can go into the M shell is ....................

(k) The subatomic particle not present in a hydrogen atom is ....................

(l) The electron has .................... charge, the proton has .................... charge, and the neutron has .................... charge.

An element is represented as ${}_{20}{}^{40}A$.

(a) What is its atomic number?

(b) What is its mass number?

(c) What is the number of protons in its nucleus?

(d) What is the number of electrons in its atom?

(e) What is the number of neutrons in its nucleus?

(g) What is its valency?

Define the term -'mass number ‘of an atom. If an atom ’B' has mass number 35 and atomic number 17, state the number of protons , electrons, and neutrons it contains