Last updated date: 29th Dec 2022 Show • Total views: 152.4k • Views today: 15.20k Answer Verified Hint: Ionic compounds are molecules that form through the gain and loss of electrons. A metal atom that loses an electron takes on a positive electric charge; a non-metal that gains an electron becomes negatively charged. Because opposite charges attract, the two atoms stick together, forming a strong, stable chemical bond. Complete answer: Note: Nonmetals tend to gain electrons in order to achieve a full outer shell, so they are said to have high electronegativities. Alkaline metals, for example, would find it much easier to lose electrons than gain electrons, so they are not very electronegative. On the other hand, halogens such as chlorine only need to gain one electron to form a full outer shell. This is much easier than losing seven electrons instead. When it comes to transition metals it is a little more complicated, but like many other metals, they also have low electronegativities. Transition metals have #(n-1)d# and #ns# orbitals which have many electrons similar in energy, meaning that it is sometimes easy for many of those electrons to be lost. This is also the reason why metals have a high electrical conductivity (i.e. their electrons are can easily move from atom to atom).
Most atoms do not have eight electrons in their valence electron shell. Some atoms have only a few electrons in their outer shell, while some atoms lack only one or two electrons to have an octet. In cases where an atom has three or fewer valence electrons, the atom may lose those valence electrons quite easily until what remains is a lower shell that contains an octet. Atoms that lose electrons acquire a positive charge as a result because they are left with fewer negatively charged electrons to balance the positive charges of the protons in the nucleus. Positively charged ions are called cations. Most metals become cations when they make ionic compounds. CationsA neutral sodium atom is likely to achieve an octet in its outermost shell by losing its one valence electron. \[\ce{Na \rightarrow Na^{+} + e^{-}} \nonumber \] The cation produced in this way, Na+, is called the sodium ion to distinguish it from the element. The outermost shell of the sodium ion is the second electron shell, which has eight electrons in it. The octet rule has been satisfied. Figure \(\PageIndex{1}\) is a graphical depiction of this process.  AnionsSome atoms have nearly eight electrons in their valence shell and can gain additional valence electrons until they have an octet. When these atoms gain electrons, they acquire a negative charge because they now possess more electrons than protons. Negatively charged ions are called anions. Most nonmetals become anions when they make ionic compounds. A neutral chlorine atom has seven electrons in its outermost shell. Only one more electron is needed to achieve an octet in chlorine’s valence shell. (In table salt, this electron comes from the sodium atom.) \[\ce{e^{-} +Cl -> Cl^{-}} \nonumber \] In this case, the ion has the same outermost shell as the original atom, but now that shell has eight electrons in it. Once again, the octet rule has been satisfied. The resulting anion, Cl−, is called the chloride ion; note the slight change in the suffix (-ide instead of -ine) to create the name of this anion. Figure \(\PageIndex{2}\) is a graphical depiction of this process.
In many cases, elements that belong to the same group (vertical column) on the periodic table form ions with the same charge because they have the same number of valence electrons. Thus, the periodic table becomes a tool for remembering the charges on many ions. For example, all ions made from alkali metals, the first column on the periodic table, have a 1+ charge. Ions made from alkaline earth metals, the second group on the periodic table, have a 2+ charge. On the other side of the periodic table, the next-to-last column, the halogens, form ions having a 1− charge. Figure \(\PageIndex{3}\) shows how the charge on many ions can be predicted by the location of an element on the periodic table. Note the convention of first writing the number and then the sign on a ion with multiple charges. The barium cation is written Ba2+, not Ba+2. Contributions & AttributionsWhy do metals tend to lose electrons to form positive ions?Metals tend to form positive (+ charged) ions because they have low numbers of valence electrons, which they can lose easily. Nonmetals tend to form negative (- charged) ions because they have a higher number of valence electrons so they tend to gain electrons easily.
What loses electrons to form positive ions?Atoms that lose electrons acquire a positive charge as a result because they are left with fewer negatively charged electrons to balance the positive charges of the protons in the nucleus. Positively charged ions are called cations. Most metals become cations when they make ionic compounds.
Why do metals always lose electrons?Metal atoms lose electrons to nonmetal atoms because metals typically have relatively low ionization energies. Metals at the bottom of a group lose electrons more easily than those at the top. That is, ionization energies tend to decrease in going from the top to the bottom of a group.
Do metals lose electrons to become positive?Metals tend to lose electrons and form positively charged ions called cations. Non-metals tend to gain electrons and form negatively charged ions called anions.
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Why do metals lose electrons to form positive ions?
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