form 2 chemistry – chemistrytutor.com

Why is an atom said to be electrically neutral?

In any given atom, the number of protons in the nucleus of an atom equals to the number of electrons in the energy level. The protons are positively charged while the electrons are negatively charged. For example, a sodium atom has 11p ,11e and 12n , the neutrons have no charge. The protons therefore hasContinue reading “Why is an atom said to be electrically neutral?”

Isotopes

Isotopes are atoms of the same element, with the same atomic numbers but different mass numbers . Why do isotopes occur ? This is due to the difference in the number of neutrons in the nucleus of these atoms . Carbon has two isotopes, Carbon -12 and Carbon – 14 . Browse on

The first 20 element in the periodic table

The periodic table consists of elements arranged according to their atomic numbers . In this sub topic , we will look at those element from atomic number 1 to 20 . Am sure almost every learner develops a way of identifying the elements in an order starting with the 1st to the 20th . HiContinue reading “The first 20 element in the periodic table”

Structure of an atom ⚛️

ATOMIC NUMBER AND ATOMIC MASS ( MASS NUMBER). – Atomic number: is the number of protons in the nucleus of an atom . Q. What is the atomic number of elements X with 5 electron in it’s energy levels ? Explain. -Element X has atomic number 5 , this is because it has 5e which equals the number of protons , therefore it has 5p which equals the atomic number. Atomic number= no. of protons= no. of electrons Mass Number ( Atomic mass ) : is the sum of the protons and neutrons in the nucleus of an atom. Mass number= protons (p) + neutrons (n) Q. An element Y has 8 protons , 8 electrons and 8 neutrons, find the mass number of the element Y. Mass number= p+ n = 8+8 = 16. Q. A Magnesium atom has atomic mass of 24 and atomic number 12 , how many neutrons are there in the magnesium atom ? Atomic number = p Atomic mass also known as mass number = p+n Therefore ; neutrons= atomic mass – no. of protons n = 24-12 n= 12. – Both mass number and atomic number can be written along with the symbol of an element. – Mass number is written as the superscript (above the symbol) while atomic number is written as a subscript ( below the symbol) to the left of the chemical symbol .

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