Periodicity in Chemistry

Atomic radii decrease from left to right across a period.

It is due to the increasing number of protons as the electrons are being added to the same shell.

Mg has its outer electrons in the 3s subshell, whereas Al is starting to fill the 3p subshell, making Al's electron slightly easier to remove.

<p>Sulfur's outer electron is being paired up with another electron in the same 3p orbital, resulting in a slight repulsion between the two negatively charged electrons.</p> Signup and view all the answers

<p>The classification of elements is based on which orbitals the highest energy electrons are in.</p> Signup and view all the answers

<p>Periodicity is the repeating pattern of physical or chemical properties going across the periods.</p> Signup and view all the answers

<p>Metallic bonding, which gets stronger as the number of electrons in the outer shell increases because more electrons are released to the sea of electrons, resulting in stronger bonds.</p> Signup and view all the answers

<p>Si has a very high melting and boiling point due to macromolecular bonding, which involves many strong covalent bonds between atoms that require high energy to break.</p> Signup and view all the answers

<p>Simple molecular bonding, which involves weak van der Waals forces between molecules, is responsible for the low melting and boiling points. S8 has a higher melting point than P4 because it has more electrons, resulting in stronger van der Waals forces between molecules.</p> Signup and view all the answers

<p>Ar has a very low melting and boiling point due to monoatomic bonding, which involves weak van der Waals forces between individual atoms.</p> Signup and view all the answers

<p>The trend in period 2 is similar to that in period 3, with a significant drop in melting and boiling points between Be and B, and N and O, due to the change from metallic to macromolecular bonding, and then to simple molecular bonding.</p> Signup and view all the answers

<p>The increase in melting and boiling points from Na to Al is due to the increase in the number of electrons in the outer shell, which results in stronger metallic bonds, requiring higher energy to break.</p> Signup and view all the answers