Which of the following reacts with HCl with great difficulty ?

• NaOH

• Ca(OH)₂

• KOH

• Zn(OH)₂

The Atomic numbers of Mn, Fe and Co are 25, 26 and 27 respectively. The order of Magnetic moments among the following is

• [Fe(CN)₆]⁴⁻ → [MnCl₄]²⁻ → [CoCl₄] ²⁻

• [MnCl₄]²⁻ → [Fe(CN)₆]⁴⁻ → [CoCl₄]²⁻

• [MnCl4]2− → [CoCl4]2− → [Fe(CN)6] 4−

• [Fe(CN)6]4− → [CoCl4]2− → [MnCl4]2

All of the following elements, their compounds could be paramagnetic or diamagnetic except

• Copper

• Vanadium

• Iron

• scandium

if the atomic mass of manganese is 54.8 and its atomic radius is 135 pm. knowing that the volume of a sphere is calculated from the law (V=4/3πr³ ). while the atomic mass of iron is 55.9. which one of the two metals sink faster in the water

• iron sink faster

• manganese sink faster

• both sink the same

• both float on the water surface

All the following about scandium is correct, except that it ............. .

• s used as an alloy with aluminum in making baseball bats for being strong and light.

• bums in pure oxygen forming scandium oxide ScO

• reacts with HCl acid giving scandium chloride ScCl₃

• reacts with nitric acid giving scandium nitrate Sc(NO₃)₃

The ions which have the electronic configuration [Ar],3d⁶ are .......... .

• Mn²⁺/ Co²⁺

• Fe³⁺/Cr³⁺

• Cr²⁺/ Mn³⁺

• Fe²⁺ /Co³⁺

All the following compounds are attracted to the external magnetic field, except ..............

• FeCl₃

• MnO₂

• ZnCl₂

• CuSO₄

All transition metals are characterized by ........

• ability to be magnetized.

• forming coloured solutions

• electric conductivity

• several oxidation states.

we can differentiate between ZnCl₂ solution and CrCl₂ solution be

• their ability to react with HCl

• their ability to conduct electricity

• their appearance

• their thermal stability when they boiled

which of the following solutions (A,B or C) is zinc chloride

• A

• B

• C