Anse the following question
1. Define an atem
2. What is a molecule ?
3. Name the particles present in an atom,
4. define atomic number.
5. differentiate between atomic number and mass number.
6.Draw the Bohr's model of atom.
7. Define valency
8. write the symbole for the elements. Oxygen
Silicon, Boron,
carbon, Potassium,
phosphorus
9. Define an element.
Answers
Answer:
(i) Atomic number: The atomic number of an element is equal to the number of protons in the nucleus of its atom.
e.g., Oxygen has 6 protons hence atomic no. = 6.
(ii) Maas number: The mass number of an atom is equal to the number of protons and neutrons in its nucleus.
Nucleons = number of protons + number of neutrons
Example: Protons + Neutrons = Nucleus = Mass number
6 + 6 = 12
(iii)Isotopes: Isotopes are atoms of the same element which have different mass number but same atomic number.
(iv)Isobars: Isobars are atoms having the same mass number but riifteren atomic numbers.
Both calcium and argon have same mass number but different storm number.
Two uses of isotopes are:
(i) An isotope of iodine is used in the treatment of goitre.
(ii) An isotope of uranium is used as a fuel in nuclear reactors.