Most Repeated MDCAT Chemistry: D and f Block Elements MCQs

Explanation

Zinc (Zn) is considered a non-typical transition element because it does not exhibit typical transition metal properties like variable oxidation states or the formation of colored compounds. It has a full d subshell in its electron configuration, which sets it apart from other transition elements.

Explanation

The electron configuration of Fe²⁺ is [Ar] 3d⁶. In the 3d orbital, there are 4 unpaired electrons.

Explanation

This is the correct answer. An amine (NH2) is a neutral ligand because it does not carry a net charge.

Explanation

The answer to the question should be option C because Zinc does not show the variable valency as elements of the d-block. After all, the d-orbital is full. Its outer electronic configuration is 3d^10 4s^2 So, they tend to lose only 2 electrons from its outermost shell. Hence, only show a valency of +2 and no variable valency.

Explanation

The correct answer is that chromium compounds in which the oxidation state of chromium is 2+ behave as strong reducing agents. This is due to their ability to easily donate electrons, thereby reducing other substances and becoming oxidized themselves to higher oxidation states such as +3, +4, or +6.Option A, a strong oxidizing agent, is incorrect because chromium in the +2 state is more likely to be oxidized than to oxidize other substances. Option C, a very weak oxidizing agent, is incorrect for similar reasons, as it downplays the reducing capability of chromium(II).

Explanation

d-d transitions are electronic transitions that occur between the molecular orbitals that are mostly metallic in character; specifically between the d-orbitals of a transition metal complex. When electronic transitions occur between these orbitals, the color observed is complementary to the wavelengths absorbed in the visible region.

Explanation

Potassium ferrocyanide, with the chemical formula K4Fe(CN)6, is considered a double salt. It is formed by the combination of two different salts: potassium cyanide (KCN) and iron(II) cyanide (Fe(CN)2). Therefore, option c is correct.

Explanation

Magnesium Oxide (MgO) has a high melting point that makes it so that it doesn't burn under low pressure and high temperature.

Explanation

To calculate the number of photons per second of infrared radiation produced by the infrared lamp, we can use the energy and efficiency of the lamp. The energy emitted per second is equal to the power, which is 100 joules/second. Effective energy emitted per second = 0.12 * 100 joules/second = 12 joules/second The energy of a single photon is given by Planck's equation: E = hc/λ Where E is the energy of a photon, h is Planck's constant (6.626 x 10^-34 J·s), c is the speed of light (3.0 x 10^8 m/s), and λ is the wavelength of the radiation (1500 nm = 1.5 x 10^-6 m).