write the number of electrons protons and neutrons present in the following element :-
(i) nitrogen (atomic weight =14 and atomic number =7)
(ii) magnesium (atomic weight =24 and atomic number =12)
Answers
Answer:
All matter, including mineral crystals, is made up of atoms, and all atoms are made up of three main particles: protons, neutrons, and electrons. As summarized in Table 2.1, protons are positively charged, neutrons are uncharged and electrons are negatively charged. The negative charge of one electron balances the positive charge of one proton. Both protons and neutrons have a mass of 1, while electrons have almost no mass.
Table 2.1 Charges and masses of the particles within atoms
Elementary Particle Charge Mass
Proton +1 1
Neutron 0 1
Electron −1 ~0
The element hydrogen has the simplest atoms, each with just one proton and one electron. The proton forms the nucleus, while the electron orbits around it. All other elements have neutrons as well as protons in their nucleus, such as helium, which is depicted in Figure 2.2. The positively charged protons tend to repel each other, and the neutrons help to hold the nucleus together. The number of protons is the atomic number, and the number of protons plus neutrons is the atomic mass. For hydrogen, the atomic mass is 1 because there is one proton and no neutrons. For helium, it is 4: two protons and two neutrons.
For most of the 16 lightest elements (up to oxygen) the number of neutrons is equal to the number of protons. For most of the remaining elements, there are more neutrons than protons, because extra neutrons are needed to keep the nucleus together by overcoming the mutual repulsion of the increasing numbers of protons concentrated in a very small space. For example, silicon has 14 protons and 14 neutrons. Its atomic number is 14 and its atomic mass is 28. The most common isotope of uranium has 92 protons and 146 neutrons. Its atomic number is 92 and its atomic mass is 238 (92 + 146).
Explanation:
i hope u understand dear
Answer:
(i) No. of electrons= No. of protons = Atomic number
= 7
No. of neutrons= Atomic weight - no. of protons
= 14-7
= 7
(ii) no. of electrons= no. of protons= Atomic number
= 12
no. of neutrons= Atomic weight-no. of protons
= 24-12
= 12
Hope it helps you!