CONSTITUENTS OF AN ATOM
The atom as explained earlier is made up of three sub-atomic particles. they are the
i. Protons,
ii. Electrons and
iii. Neutrons.
the Protons are positively charged.
the Electrons are negatively charged while
the Neutrons have no charge (neutral)
sub-atomic particles charge mass
1. Protons + (positive) 1 (unit)
2. Electrons - (negative) 0.00005
3. Neutrons 0 (neutral) 1 (unit)
Atomic number: - Of an element is the number of protons in the nucleus of the atom of the element.
atomic numbers are whole numbers and there are NO two elements in the world that have the same atomic number.
Mass number or atomic mass: - of an element is the sum of the protons and neutrons in the nucleus of one atom of the element.
that is,
Atomic Mass = Number of protons + Number of neutrons
In chemistry an element X can be represented as AZX
where A = Atomic mass or mass number
Z = Atomic number
atomic no = 20 (number of protons)
Elements Num. of P Num. of E Num. of N
40
1. 20 Ca 20 20 20
14
2. 7 N 7 7 14
39
3. 19 K 19 19 20
THEORY QUESTIONS
1.a(i) State the constituents of an atom.
(ii) What is the number of protons, neutrons and electrons in the following elements
(a). 115B (b) 126C (c.) 2311Na (d) 3216S
1a(i) How many neutrons are present in the isotope 37Cl17 ?
(ii) State the number of electrons, protons and neutrons present in the following atoms/ions
a) Ca b) S2- c) Al3+ d) P
b(i) Determine the number of electrons, protons and neutrons in each of the following: 39K19, 63.5Cu29
No comments:
Post a Comment