This is due to the phenomenon known as the Inert pair effect.
Orbitals shield better with a lower azimuthal quantum number(l). Hence, s orbitals shield better than p which shields better than d which is better than f, etc.
The electronic configuration of Si is [Ne] 3s²3p². The 2s and 2p orbitals are shielding the electrons from the nucleus. So the s and p electrons are ready to be ionized. And hence shows a +4 oxidation state.
Similarly, as we move down the group, atomic size increases, and metallic character also increases. Also, lead is below Si and a lower oxidation state is more stable down the group. Hence lead shows a +2 oxidation state.
To learn more about the oxidation state, visit: brainly.com/question/11313964
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Answer:
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Explanation:
Hello,
In this case, for the mole fraction of methanol we use the formula:

Thus, we compute the moles of both water (molar mass 18 g/mol) and methanol (molar mass 32 g/mol):

Hence, mole fraction is:

Next, mass percent is:

And the molality, considering the mass of water in kg (0.185 kg):

Regards.
i believe the answer is...
Atoms of isotopes of an element have different numbers of protons.
Explanation:
On the basis of electrical conductivity, materials are classified as conductors, semi-conductors and non-conductors. Conductors : Substances through which electricity can easily pass through are known as conductors. For example, copper, silver, mercury etc are good conductors of electricity