The number of unit positive charges carried by the nucleus of an atom is termed as the atomic number. Since the positive charge on the nucleus is due to the presence of protons in it and each proton carries one unit positive charge, therefore, the atomic number is numerically equal to the number of protons present in the nucleus of an atom.
The sum of the neutrons and protons is known as mass number. Mass number is generally represented by the letter A. Therefore, from the knowledge of atomic number and mass number of an element, the number of electrons, protons and neutrons can be easily predicted.
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The sum of the neutrons and protons is known as mass number. Mass number is generally represented by the letter A. Therefore, from the knowledge of atomic number and mass number of an element, the number of electrons, protons and neutrons can be easily predicted.
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By following this channel it is very useful for the development of this channel. The Dailymotion application is easy to install on any smartphone, and does not take up much memory space.
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LearningTranscript
00:01Hi friends, education is the key to opening the door to new opportunities.
00:07An atom consists of an atomic nucleus and a number of electrons revolving around it.
00:15The same atom will have the same properties. Different atoms will have different properties.
00:23The image on this screen is an oxygen atom.
00:27The only problem here is how to express this atom so that it is easy to recognize without having to draw it.
00:36It is very troublesome if we always draw atoms like on a piece of paper.
00:43In general, we can express atoms with certain symbols.
00:49X is the symbol of an atom.
00:53In general, the symbol of an atom is an abbreviation of its name, O for oxygen.
01:02Z is the atomic number.
01:06This is the number of unit positive charges carried by the nucleus of an atom.
01:12Since the positive charge on the nucleus is due to the presence of protons in it,
01:18and each proton carries one unit positive charge.
01:22Therefore, the atomic number is numerically equal to the number of protons present in the nucleus of an atom.
01:31There are eight blue balls.
01:34That indicates eight units of protons.
01:37The value of Z is eight.
01:41Moreover, the number of protons in an atom is equal to the number of electrons since the atom on the whole is electrically neutral.
01:51Thus, the atomic number of an element is equal to the number of protons present in the nucleus or the number of electrons present outside the nucleus.
02:04Since the electrons are of negligible mass, the entire mass of the atom is due to protons and neutrons only.
02:19These particles are present in the nucleus and are collectively known as nucleons.
02:25The sum of the neutrons and protons is known as mass number.
02:32There are eight blue balls and eight pink balls.
02:37That represents eight units of protons and eight units of neutrons.
02:43The value of a is 16 because that is the number of protons and neutrons.
02:51Overall, we can write the oxygen atom with a symbol like this.
02:57When we find an atom with this symbol, we know that it is an oxygen atom.
03:03An oxygen atom has eight electrons, eight protons, and eight neutrons.
03:10Happy learning everyone!