Sorry, that is incorrect.

The only correct answer is: 503 , 965 , 3458 , 4530

• 1000 , 2251 , 3361 , 4564 is not correct because there is no significant rise from the second to the third IE. Therefore, it is not a Group 2 element.
• 496 , 4563 , 6913 , 9544 is not correct because there is a significant rise between the first and second IEs, indicating a Group 1 element.
• 578 , 1817 , 2745 , 11578 is not correct because there is a significant rise from the third to the fourth IE, indicating a Group 3 element.

Sorry, that is incorrect.

The only correct answer is: $Mn^{2+}$

• $Cr^{3+}$ is incorrect because it is $3d^{3}$ not $3d^{5}$
• $Fe^{2+}$ is incorrect because it is $3d^{6}$ not $3d^{5}$
• $Mn^{3+}$ is incorrect because it is $3d^{4}$ not $3d^{5}$

Sorry, that is incorrect.

The only correct answer is: 801 , 2427 , 3660 , 25,026

• 1086 , 2353 , 4621 , 6223 is incorrect because this does not show a large increase for the fourth ionization, so it is not in group 3.
• 900 , 1757 , 14,849 , 21,007 is incorrect because it shows a large increase for the third ionization, so it is in group 2.
• 578 , 1817 , 2745 , 11,578 is incorrect because it is a group 3 element as it has a large increase for the fourth ionization, but it has a first ionization energy that is lower than that of the correct option. So it is below it in Group 3. So it cannot be Boron.

Sorry, that is incorrect.

The only correct answer is: 12 

• 5 is incorrect because this is the number of electrons in the 3p orbitals of the chlorine atom
• 6 is incorrect because this is only the number of electrons in the 3p orbitals of the chloride ion
• 18 is incorrect because this is the total number of electrons in the chloride ion, not just those in the p orbitals.

Sorry, that is incorrect.

The only correct answer is: nucleophile

• alkali is not correct because $OH^{-}$ does not neutralise an acid in this reaction
• catalyst is not correct because the $OH^{-}$ ions are used up in this reaction
• electrophile is not correct because $OH^{-}$ is looking to react with an electron-deficient area, not an electron-rich one.

Sorry, that is incorrect.

The only correct answer is: carbon particulates

• carbon particulates is incorrect because oxides of nitrogen are not black solids
• oxides of sulfur is incorrect because oxides of sulfur are not black
• unburnt hydrocarbons is incorrect because unburnt hydrocarbons are not black solids

Sorry, that is incorrect.

The only correct answer is: no change

• orange to green is not correct because tertiary alcohol is not oxidized
• green to orange is not correct because this is an incorrect colour change for acidified dichromate
• purple to colourless is not correct because this is an incorrect colour change for these reagents.

Sorry, that is incorrect.

The only correct answer is: giant ionic

Sorry, that is incorrect.

The only correct answer is: anions and cations.

• atoms and delocalized electrons is incorrect because ionic bonding involves positive ions and negative ions
• cations and delocalized electrons is incorrect because there are no delocalized electrons in ionic bonding
• two nuclei and a shared pair of electrons is incorrect because this is a description of covalent bonding

Sorry, that is incorrect.

The only correct answer is: $CO_{2}$

• $H_{2}S$ is not correct because it has a similar shape to water.
• $SO_{2}$ is not correct because it has a trigonal planar shape, resulting from the lone pair and two groups of electrons in the two double bonds.
• $CH_{2} = CH_{2}$ is not correct because it is planar but not linear.