All Solutions
Page 191: Check Your Understanding
A sodium ion and a sodium atom both have the same number of protons. Sodium ion however has 10 electrons while sodium atom has 11 electrons. Sodium ion is positively charged while sodium atom is electrically neutral.
A sodium ion and a neon atom both have the same number of electron. Sodium ion however has 11 protons while neon atom has 10 protons. Sodium ion is positively charged while neon atom is electrically neutral.
Atomic structure of Lithium atom:
Atomic structure of an Lithium ion:
Chemical symbol of lithium ion is Li$^+$, where the positive charge indicates that the atom has lost 1 electron to form an ion.
Lithium ion has only its K-shell filled. This implies that this has the same electron arrangement as the noble gas Helium.
Mg$^{+2}$ is the chemical symbol of magnesium ion, formed by the magnesium atom losing 2 of its outermost electrons.
S$^{-2}$ is the chemical symbol of sulfur ion called the sulfide ion, formed by the sulfur atom gaining 2 electrons to complete its outermost shell.
Fe$^{+3}$ is the chemical symbol of iron-3 ion, formed by the iron atom losing 3 of its outermost electrons.
Br$^{-}$ is the chemical symbol of bromine ion called the bromide ion, formed by the bromine atom gaining 1 electron to complete its outermost shell.
N$^{-3}$ is the chemical symbol of nitrogen ion called the nitride ion, formed by the nitrogen atom gaining 3 electrons to complete its outermost shell.
S$^{-2}$ is the sulfide ion formed by the sulfur atom gaining 2 electrons to complete its outermost shell and achieve a stable electronic configuration. The atomic number of sulfur is 16 and the number of electrons in the sulfide ion are $16+2=18$. This is the same number of electrons as in Argon atom as well as potassium ion.
Al$^{+3}$ is the aluminum ion formed by the aluminum atom losing 3 electrons to complete its outermost shell and achieve a stable electronic configuration. The atomic number of aluminum is 13 and the number of electrons in the aluminum ion are $13-3=10$. This is the same number of electrons as in Neon atom as well as sodium ion.
P$^{-3}$ is the phosphide ion formed by the phosphorus atom gaining 3 electrons to complete its outermost shell and achieve a stable electronic configuration. The atomic number of phosphorus is 15 and the number of electrons in the phosphide ion are $15+3=18$. This is the same number of electrons as in Argon atom as well as sulfide ion.
Kr is the krypton atom. This is a noble gas. It has 36 electrons. This is the same number of electrons as in bromide ion as well as rubidium ion.
Cs$^{+}$ is the caesium ion formed by the caesium atom losing 1 electron to complete its outermost shell and achieve a stable electronic configuration. The atomic number of caesium is 55 and the number of electrons in the caesium ion are $55-1=54$. This is the same number of electrons as in Xenon atom as well as iodide ion.
The family of alkaline earth metals lies in group II of the periodic table indicating that each member of this family has 2 valence electrons. This therefore implies that the new element must also have only 2 electrons in its outermost orbit.
The family of alkaline earth metals lies in group II of the periodic table indicating that each member of this family has 2 valence electrons. They therefore form ions by losing these 2 valence electrons and obtaining a $+2$ charge on its ion. This therefore implies that the new element must also have a $+2$ charge in its ionic form.
The ion K$^{+2}$ indicates that the potassium ion has lost 2 electrons. There are a total of 19 electrons in potassium atom, by losing 2 electrons, its electrons reduce to $19-2=17$. This implies that there are 7 electrons in its outermost orbit which forms an unstable ion as its outermost orbit does not have a noble gas stable configuration. Therefore, this ion ceases to exists in normal conditions.
The ion O$^{-}$ indicates that the oxygen ion has gained 1 electron. There are a total of 8 electrons in oxygen atom, by gaining 1 electron, its electrons increase to $8+1=9$. This implies that there are 7 electrons in its outermost orbit which forms an unstable ion as its outermost orbit does not have a noble gas stable configuration. Therefore, this ion ceases to exists in normal conditions.
The group number of an element in the periodic table indicates the number of the electrons in its outermost orbit. This implies that the atoms of elements in group I form ions by losing their 1 valence electron and obtaining a charge of $+1$ on them. Similarly, the atoms of elements in group II form ions by losing their 2 valence electrons and obtaining a charge of $+2$ on them. Similarly, the atoms of elements in group III form ions by losing their 3 valence electrons and obtaining a charge of $+3$ on them.
The group number of an element in the periodic table indicates the number of the electrons in its outermost orbit. This implies that the atoms of elements in group 15 form ions by gaining 3 electrons to obtain stable configuration and obtaining a charge of $-3$ on them. Similarly, the atoms of elements in group 16 form ions by gaining 3 electrons to obtain stable configuration and obtaining a charge of $-2$ on them. Similarly, the atoms of elements in group 17 form ions by gaining 1 electron to obtain stable configuration and obtaining a charge of $-1$ on them.
