First, isotopes <u>are the atoms of a single element whose nuclei have a different number of neutrons</u>, and therefore, differ in mass numbers. You should know that atoms are formed by a nucleus that has a small size and is made up of protons and neutrons. The nucleus is surrounded by a cloud of electrons, which are found in a region of the atom called the cortex.
The mass number, represented as A, <u>is the sum of the number of protons and neutrons in the nucleus</u>. On the other hand, the atomic number (Z) is <u>the number of protons that exist in the nucleus.
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The isotopes of an element X are represented as follows,
<em>(see first attached picture)</em>
It should be noted that the number of neutrons of a chemical element can be calculated as the difference A-Z.
<u>The atomic and mass numbers of bismuth with 125 neutrons are</u>:
Z = 83
A = 83 + 125 = 208
Thus, the atomic symbol of the bismuth isotope with 125 neutrons is:
<em>(see second attached picture)</em>
<h3>
In reference to the diagram attached </h3><h3>
Answer:</h3>
one battery, two switches, and three light bulbs
Explanation:
- A circuit is an arrangement that shows the flow of electrons from a current source such as a battery.
- The diagram shows a circuit that contains one battery, two switches, and three light bulbs.
- The switches serves to close the circuit when necessary.
- The battery supplies current to the circuit.
- The light bulbs are used for lighting.
Answer: C
Explanation: Pesticides protect our crops, but some studies show that they cause consumers to gain weight:)