Answer: b. One atom transferring electrons to another atom
Explanation: An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element and the element which accepts the electrons is known as electronegative element. This bond is formed between a metal and an non-metal.
Covalent bonds are formed by sharing of electrons between non metals
For example, In calcium iodide the one electron from calcium metal gets transferred to iodine atom and thus form an ionic bond to give 
Electronic configuration of calcium:
![[Ca]=1s^22s^22p^63s^23p^64s^2](https://tex.z-dn.net/?f=%5BCa%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E2)
Calcium atom will lose two electron to gain noble gas configuration and form calcium cation with +2 charge.
![[Ca^{2+}]=1s^22s^22p^63s^23p^6](https://tex.z-dn.net/?f=%5BCa%5E%7B2%2B%7D%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E6)
Electronic configuration of iodine:
![[I]=1s^22s^22p^63s^23p^64s^23d^{10}4p^5](https://tex.z-dn.net/?f=%5BI%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E23d%5E%7B10%7D4p%5E5)
Iodine atom will gain one electron to gain noble gas configuration and form iodide ion with -1 charge.
![[I^-]=1s^22s^22p^63s^23p^64s^23d^{10}4p^6](https://tex.z-dn.net/?f=%5BI%5E-%5D%3D1s%5E22s%5E22p%5E63s%5E23p%5E64s%5E23d%5E%7B10%7D4p%5E6)
1) in periodic acid (HIO₄), iodine has oxidation number +7, hydrogen has oxidation number +1, oxygen has -2, compound has neutral charge:
+1 + x + 4 · (-2) = 0.
x = +7.
2) in molecule of iodine (I₂), iodine has oxidation number 0, because iodine is nonpolar molecule.
3) in sodium iodide (NaI), iodine has oxidation number -1, sodium has oxidation number +1:
+1 + x = 0.
x = -1.
4) in iodic acid (HIO₃), iodine has oxidation number +5, hydrogen has oxidation number +1, oxygen has -2, compound has neutral charge:
+1 + x + 3 · (-2) = 0.
x = +5.
The chemical properties of an atom are determined by the number of the electrons while bonding is determined by the arrangement and the valency of the electrons.
<h3>What is an Atom?</h3>
The smallest component of ordinary stuff that makes up a chemical element is an atom. Atoms that are neutral or ionized make up every solid, liquid, gas, and form of plasma. Atoms are incredibly tiny, measuring typically 100 picometers across. Due to quantum effects, they are so small that it is impossible to predict their behavior with sufficient accuracy using classical physics, as would be the case, for example, if they were tennis balls.
Each atom is made up of a nucleus and one or more electrons that are linked to it. One or more protons and a significant number of neutrons make up the nucleus. Only the most prevalent type of hydrogen is neutron-free. The nucleus of an atom contains more than 99.94% of its mass.
Learn more about Atom with the help of the given link:
brainly.com/question/22114450
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27*9=243 if one mole is equal to 27 grams times that by 9
