Video Transcript
Fill in the blanks. Metals tend to blank electrons
during chemical reactions to form blank ions. (A) Lose, positive; (B) gain,
negative; (C) lose, negative; (D) gain, positive.
In this question, we need to choose
the two correct words to fill in the blanks and complete the statement. First of all, metal atoms tend to
have less than four electrons in their outermost energy level. A sodium atom is an example of a
metal atom. We can see in the energy level
diagram that a sodium atom has one electron in its outermost energy level. On the other hand, nonmetal atoms
tend to have more than four electrons in their outermost energy level. A chlorine atom is an example of a
nonmetal atom. We can see in the energy level
diagram that a chlorine atom has seven electrons in its outermost energy level.
When sodium reacts with chlorine,
each sodium atom loses the one electron in its outer energy level. When chlorine reacts, each chlorine
atom gains one electron in its outer energy level.
Let’s summarize how atoms lose or
gain electrons using these examples. When metals react, their atoms tend
to lose electrons. And when nonmetals react, their
atoms tend to gain electrons. This means that answer choices (B)
and (D) are incorrect because metals tend to lose electrons during chemical
reactions, not gain them.
Let’s take a look at our example
atoms again. When a sodium atom loses an
electron, it forms a positive ion. This ion has the symbol notation
Na+. A sodium atom has 11 positively
charged protons in the nucleus and 11 negatively charged electrons in the energy
levels. So, like all atoms, the sodium atom
is uncharged, or neutral. When a sodium atom loses one
electron, it ends up with 10 electrons. But it still has 11 protons in its
nucleus. So, the charge of the sodium ion is
positive one.
Now let’s take a look at
chlorine. A chlorine atom has 17 protons and
17 electrons. When a chlorine atom gains one
electron, it ends up with 18 electrons. But it only has 17 protons in its
nucleus. So, the charge of the chloride ion
is negative one. So now we know that when the
chlorine atom gains an electron, it forms a negative ion.
These examples have helped us to
see that metals tend to form positive ions and nonmetals tend to form negative ions
during chemical reactions. Therefore, answer choice (A) must
be the correct answer. Metals tend to lose electrons
during chemical reactions to form positive ions.
