`color{green}("𝐎𝐱𝐢𝐝𝐚𝐭𝐢𝐨𝐧 𝐬𝐭𝐚𝐭𝐞𝐬 𝐚𝐧𝐝 𝐭𝐫𝐞𝐧𝐝𝐬 𝐢𝐧 𝐜𝐡𝐞𝐦𝐢𝐜𝐚𝐥 𝐫𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 :")`
`color{green}(★)` The group 14 elements have four electrons in outermost shell.
`color{green}(★)` The common oxidation states exhibited by these elements are `+4` and `+2`.
`color{green}(★)` Carbon also exhibits negative oxidation states.
`color{green}(★)` Since the sum of the first four ionization enthalpies is very high, compounds in +4 oxidation state are generally covalent in nature.
`color{green}(★)` In heavier members the tendency to show `+2` oxidation state increases in the sequence `color{red}(Ge < Sn < Pb)`. It is due to the inability of `color{red}(ns^2)` electrons of valence shell to participate in bonding. The relative stabilities of these two oxidation states vary down the group.
`color{green}(★)` Carbon and silicon mostly show `+4` oxidation state. Germanium forms stable compounds in `+4` state and only few compounds in `+2` state. Tin forms compounds in both oxidation states (`color{red}(Sn)` in `+2` state is a reducing agent).
`color{green}(★)` Lead compounds in +2 state are stable and in `+4` state are strong oxidising agents.
`color{green}(★)` In tetravalent state the number of electrons around the central atom in a molecule (e.g., carbon in `color{red}(C Cl_4)`) is eight.
`color{green}(★)` Being electron precise molecules, they are normally not expected to act as electron acceptor or electron donor species. Although carbon cannot exceed its covalence more than `4`, other elements of the group can do so. It is because of the presence of d orbital in them. Due to this, their halides undergo hydrolysis and have tendency to form complexes by accepting electron pairs from donor species. For example, the species like, `color{red}(SiF_6^(2–))`, `color{red}([GeCl_6]^(2–))`,` color{red}([Sn(OH)_6]^(2–))` exist where the hybridisation of the central atom is `color{red}(sp^3d^2).`
`color{green}("(𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐨𝐱𝐲𝐠𝐞𝐧 :")`
`color{brown}(★)` All members when heated in oxygen form oxides.
`color{brown}(★)` There are mainly two types of oxides, i.e., monoxide and dioxide of formula `color{red}(MO)` and `color{red}(MO_2)` respectively.
`color{brown}(★)` `color{red}(SiO)` only exists at high temperature.
`color{brown}(★)` Oxides in higher oxidation states of elements are generally more acidic than those in lower oxidation states.
`color{brown}(★)` The dioxides `color{red}(— CO_2, SiO_2)` and `color{red}(GeO_2)` are acidic, whereas `color{red}(SnO_2)` and `color{red}(PbO_2)` are amphoteric in nature.
`color{brown}(★)` Among monoxides, `color{red}(CO)` is neutral, `color{red}(GeO)` is distinctly acidic whereas `color{red}(SnO)` and `color{red}(PbO)` are amphoteric.
`color{green}("(𝐢𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐰𝐚𝐭𝐞𝐫 : ")`
`color{brown}(★)` Carbon, silicon and germanium are not affected by water.
`color{brown}(★)` Tin decomposes steam to form dioxide and dihydrogen gas.
`color{red}(Sn + 2H_2O overset(Delta)→ SnO_2+2H_2)`
`color{brown}(★)` Lead is unaffected by water, probably because of a protective oxide film formation.
`color{green}("(𝐢𝐢𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐡𝐚𝐥𝐨𝐠𝐞𝐧: ")`
`color{brown}(★)` These elements can form halides of formula `color{red}(MX_2)` and `color{red}(MX_4)` (where `color{red}(X = F, Cl, Br, I)` ).
`color{brown}(★)` Except carbon, all other members react directly with halogen under suitable condition to make halides. Most of the `color{red}(MX_4)` are covalent in nature. The central metal atom in these halides undergoes `color{red}(sp^3)` hybridisation and the molecule is tetrahedral in shape. Exceptions are `color{red}(SnF_4)` and `color{red}(PbF_4)`, which are ionic in nature. `color{red}(PbI_4)` does not exist because `color{red}(Pb)`—I bond initially formed during the reaction does not release enough energy to unpair `color{red}(6s^2)` electrons and excite one of them to higher orbital to have four unpaired electrons around lead atom. Heavier members `color{red}(Ge)` to `color{red}(Pb)` are able to make halides of formula `color{red}(MX_2)`. Stability of dihalides increases down the group. Considering the thermal and chemical stability, `color{red}(GeX_4)` is more stable than `color{red}(GeX_2)`, whereas `color{red}(PbX_2)` is more than `color{red}(PbX_4)`. Except `color{red}(C Cl_4)`, other tetrachlorides are easily hydrolysed by water because the central atom can accommodate the lone pair of electrons from oxygen atom of water molecule in d orbital.
`color{brown}(★)` Hydrolysis can be understood by taking the example of `color{red}(SiCl_4)`. It undergoes hydrolysis by initially accepting lone pair of electrons from water molecule in `color{red}(d)` orbitals of `color{red}(Si)`, finally leading to the formation of `color{red}(Si(OH)_4)` as shown below :
`color{green}("𝐎𝐱𝐢𝐝𝐚𝐭𝐢𝐨𝐧 𝐬𝐭𝐚𝐭𝐞𝐬 𝐚𝐧𝐝 𝐭𝐫𝐞𝐧𝐝𝐬 𝐢𝐧 𝐜𝐡𝐞𝐦𝐢𝐜𝐚𝐥 𝐫𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 :")`
`color{green}(★)` The group 14 elements have four electrons in outermost shell.
`color{green}(★)` The common oxidation states exhibited by these elements are `+4` and `+2`.
`color{green}(★)` Carbon also exhibits negative oxidation states.
`color{green}(★)` Since the sum of the first four ionization enthalpies is very high, compounds in +4 oxidation state are generally covalent in nature.
`color{green}(★)` In heavier members the tendency to show `+2` oxidation state increases in the sequence `color{red}(Ge < Sn < Pb)`. It is due to the inability of `color{red}(ns^2)` electrons of valence shell to participate in bonding. The relative stabilities of these two oxidation states vary down the group.
`color{green}(★)` Carbon and silicon mostly show `+4` oxidation state. Germanium forms stable compounds in `+4` state and only few compounds in `+2` state. Tin forms compounds in both oxidation states (`color{red}(Sn)` in `+2` state is a reducing agent).
`color{green}(★)` Lead compounds in +2 state are stable and in `+4` state are strong oxidising agents.
`color{green}(★)` In tetravalent state the number of electrons around the central atom in a molecule (e.g., carbon in `color{red}(C Cl_4)`) is eight.
`color{green}(★)` Being electron precise molecules, they are normally not expected to act as electron acceptor or electron donor species. Although carbon cannot exceed its covalence more than `4`, other elements of the group can do so. It is because of the presence of d orbital in them. Due to this, their halides undergo hydrolysis and have tendency to form complexes by accepting electron pairs from donor species. For example, the species like, `color{red}(SiF_6^(2–))`, `color{red}([GeCl_6]^(2–))`,` color{red}([Sn(OH)_6]^(2–))` exist where the hybridisation of the central atom is `color{red}(sp^3d^2).`
`color{green}("(𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐨𝐱𝐲𝐠𝐞𝐧 :")`
`color{brown}(★)` All members when heated in oxygen form oxides.
`color{brown}(★)` There are mainly two types of oxides, i.e., monoxide and dioxide of formula `color{red}(MO)` and `color{red}(MO_2)` respectively.
`color{brown}(★)` `color{red}(SiO)` only exists at high temperature.
`color{brown}(★)` Oxides in higher oxidation states of elements are generally more acidic than those in lower oxidation states.
`color{brown}(★)` The dioxides `color{red}(— CO_2, SiO_2)` and `color{red}(GeO_2)` are acidic, whereas `color{red}(SnO_2)` and `color{red}(PbO_2)` are amphoteric in nature.
`color{brown}(★)` Among monoxides, `color{red}(CO)` is neutral, `color{red}(GeO)` is distinctly acidic whereas `color{red}(SnO)` and `color{red}(PbO)` are amphoteric.
`color{green}("(𝐢𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐰𝐚𝐭𝐞𝐫 : ")`
`color{brown}(★)` Carbon, silicon and germanium are not affected by water.
`color{brown}(★)` Tin decomposes steam to form dioxide and dihydrogen gas.
`color{red}(Sn + 2H_2O overset(Delta)→ SnO_2+2H_2)`
`color{brown}(★)` Lead is unaffected by water, probably because of a protective oxide film formation.
`color{green}("(𝐢𝐢𝐢) 𝐑𝐞𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲 𝐭𝐨𝐰𝐚𝐫𝐝𝐬 𝐡𝐚𝐥𝐨𝐠𝐞𝐧: ")`
`color{brown}(★)` These elements can form halides of formula `color{red}(MX_2)` and `color{red}(MX_4)` (where `color{red}(X = F, Cl, Br, I)` ).
`color{brown}(★)` Except carbon, all other members react directly with halogen under suitable condition to make halides. Most of the `color{red}(MX_4)` are covalent in nature. The central metal atom in these halides undergoes `color{red}(sp^3)` hybridisation and the molecule is tetrahedral in shape. Exceptions are `color{red}(SnF_4)` and `color{red}(PbF_4)`, which are ionic in nature. `color{red}(PbI_4)` does not exist because `color{red}(Pb)`—I bond initially formed during the reaction does not release enough energy to unpair `color{red}(6s^2)` electrons and excite one of them to higher orbital to have four unpaired electrons around lead atom. Heavier members `color{red}(Ge)` to `color{red}(Pb)` are able to make halides of formula `color{red}(MX_2)`. Stability of dihalides increases down the group. Considering the thermal and chemical stability, `color{red}(GeX_4)` is more stable than `color{red}(GeX_2)`, whereas `color{red}(PbX_2)` is more than `color{red}(PbX_4)`. Except `color{red}(C Cl_4)`, other tetrachlorides are easily hydrolysed by water because the central atom can accommodate the lone pair of electrons from oxygen atom of water molecule in d orbital.
`color{brown}(★)` Hydrolysis can be understood by taking the example of `color{red}(SiCl_4)`. It undergoes hydrolysis by initially accepting lone pair of electrons from water molecule in `color{red}(d)` orbitals of `color{red}(Si)`, finally leading to the formation of `color{red}(Si(OH)_4)` as shown below :
