Question
Read the passage given below and answer the following questions from 1 to 5 .
Group 14 elements: the carbon family-Carbon, silicon, germanium, tin lead and Flerovium are the members of group 14. Carbon Is the seventeenth most abundant element by Mass in the earth's crust. It is widely Distributed in nature in free as well as in the Combined state. In elemental state it is available As coal, graphite and diamond; however, in Combined state it is present as metal Carbonates, hydrocarbons and carbon dioxide Gas ( $0.03 \%$ ) in air. One can emphatically say That carbon is the most versatile element in the World. Its combination with other elements Such as dihydrogen, dioxygen, chlorine and Sulphur provides an astonishing array of Materials ranging from living tissues to drugs And plastics.
The valence shell electronic configuration of These elements is $ns ^2 np ^2$. The inner core of the Electronic configuration of elements in this Group also differs.
Covalent Radius There is a considerable increase in covalent Radius from C to Si, thereafter from Si to Pb a Small increase in radius is observed. This is Due to the presence of completely filled d and f Orbitals in heavier members. Ionization Enthalpy The first ionization enthalpy of group 14 Members is higher than the corresponding Members of group 13. The influence of inner Core electrons is visible here also. In general the lonisation enthalpy decreases down the group. Small decrease in $\Delta iH$ from Si to Ge to Sn and Slight increase in $\Delta i H$ from Sn to Pb is the Consequence of poor shielding effect of Intervening $d$ and $f$ orbitals and increase in size Of the atom. Electronegativity Due to small size, the elements of this group Are slightly more electronegative than group 13 elements. The electronegativity values for Elements from Si to Pb are almost the same.
Physical Properties All members of group14 are solids. Carbon and Silicon are non-metals, germanium is a metalloid, Whereas tin and lead are soft metals with low Melting points. Melting points and boiling points Of group 14 elements are much higher than those Of corresponding elements of group 13.
(i) Reactivity towards oxygen All members when heated in oxygen form Oxides. There are mainly two types of oxides, i.e., monoxide and dioxide of formula MO and $MO _2$ respectively. SiO only exists at high Temperature. Oxides in higher oxidation states Of elements are generally more acidic than Those in lower oxidation states. The dioxides $CO _2$, SiO 2 and $GeO _2$ are acidic, whereas $SnO _2$ and $PbO _2$ are amphoteric in nature. Among monoxides, CO is neutral, GeO is Distinctly acidic whereas SnO and PbO are Amphoteric.
(ii) Reactivity towards water Carbon, silicon and germanium are not Affected by water. Tin decomposes steam to Form dioxide and dihydrogen gas.
$Sn+2 H_2 O \rightarrow SnO_2+2 H_2$
Lead is unaffected by water, probably Because of a protective oxide film formation.
(iii) Reactivity towards halogen These elements can form halides of formula $M X_2$ and $M X_4$ (where $\left.X=F, C l, B r, I\right)$. Except Carbon, all other members react directly with Halogen under suitable condition to make Halides. Most of the $MX _4$ are covalent in nature. The central metal atom in these halides Undergoes $sp ^3$ hybridisation and the molecule Is tetrahedral in shape. Exceptions are $SnF _4$ And $PbF _4$, which are ionic in nature.
Carbon atoms have the tendency to link With one another through covalent bonds to Form chains and rings. This property is called Catenation. This is because C-C bonds are Very strong. Down the group the size increases and electronegativity decreases, and, thereby, Tendency to show catenation decreases. This Can be clearly seen from bond enthalpies Values. The order of catenation is $C > Si > Ge \approx Sn$. Lead does not show catenation.
Group 14 elements: the carbon family-Carbon, silicon, germanium, tin lead and Flerovium are the members of group 14. Carbon Is the seventeenth most abundant element by Mass in the earth's crust. It is widely Distributed in nature in free as well as in the Combined state. In elemental state it is available As coal, graphite and diamond; however, in Combined state it is present as metal Carbonates, hydrocarbons and carbon dioxide Gas ( $0.03 \%$ ) in air. One can emphatically say That carbon is the most versatile element in the World. Its combination with other elements Such as dihydrogen, dioxygen, chlorine and Sulphur provides an astonishing array of Materials ranging from living tissues to drugs And plastics.
The valence shell electronic configuration of These elements is $ns ^2 np ^2$. The inner core of the Electronic configuration of elements in this Group also differs.
Covalent Radius There is a considerable increase in covalent Radius from C to Si, thereafter from Si to Pb a Small increase in radius is observed. This is Due to the presence of completely filled d and f Orbitals in heavier members. Ionization Enthalpy The first ionization enthalpy of group 14 Members is higher than the corresponding Members of group 13. The influence of inner Core electrons is visible here also. In general the lonisation enthalpy decreases down the group. Small decrease in $\Delta iH$ from Si to Ge to Sn and Slight increase in $\Delta i H$ from Sn to Pb is the Consequence of poor shielding effect of Intervening $d$ and $f$ orbitals and increase in size Of the atom. Electronegativity Due to small size, the elements of this group Are slightly more electronegative than group 13 elements. The electronegativity values for Elements from Si to Pb are almost the same.
Physical Properties All members of group14 are solids. Carbon and Silicon are non-metals, germanium is a metalloid, Whereas tin and lead are soft metals with low Melting points. Melting points and boiling points Of group 14 elements are much higher than those Of corresponding elements of group 13.
(i) Reactivity towards oxygen All members when heated in oxygen form Oxides. There are mainly two types of oxides, i.e., monoxide and dioxide of formula MO and $MO _2$ respectively. SiO only exists at high Temperature. Oxides in higher oxidation states Of elements are generally more acidic than Those in lower oxidation states. The dioxides $CO _2$, SiO 2 and $GeO _2$ are acidic, whereas $SnO _2$ and $PbO _2$ are amphoteric in nature. Among monoxides, CO is neutral, GeO is Distinctly acidic whereas SnO and PbO are Amphoteric.
(ii) Reactivity towards water Carbon, silicon and germanium are not Affected by water. Tin decomposes steam to Form dioxide and dihydrogen gas.
$Sn+2 H_2 O \rightarrow SnO_2+2 H_2$
Lead is unaffected by water, probably Because of a protective oxide film formation.
(iii) Reactivity towards halogen These elements can form halides of formula $M X_2$ and $M X_4$ (where $\left.X=F, C l, B r, I\right)$. Except Carbon, all other members react directly with Halogen under suitable condition to make Halides. Most of the $MX _4$ are covalent in nature. The central metal atom in these halides Undergoes $sp ^3$ hybridisation and the molecule Is tetrahedral in shape. Exceptions are $SnF _4$ And $PbF _4$, which are ionic in nature.
Carbon atoms have the tendency to link With one another through covalent bonds to Form chains and rings. This property is called Catenation. This is because C-C bonds are Very strong. Down the group the size increases and electronegativity decreases, and, thereby, Tendency to show catenation decreases. This Can be clearly seen from bond enthalpies Values. The order of catenation is $C > Si > Ge \approx Sn$. Lead does not show catenation.
- Which of the following is not the member of group 14 ?
- boron
- silicon
- germanium
- tin
- … does not show catenation.
- Carbon
- Lead
- Silicon
- Germanium
- Which of following elements are affected by water ?
- carbon
- silicon
- germanium
- All the above
- The valence shell electronic configuration of Group 14 elements is …
- $ns^2np^4$
- $ns^2np^5$
- $ns^2np^2$
- $ns^2np^3$
- Half-life of $^{14}C$ is … years.
- 6570
- 4570
- 5770
- 1970
