Which of the following statements about chromium is correct?
Practice 2easy
Identify the actinide element that is widely used as nuclear fuel in power plants and has an atomic number of 92.
Practice 3easy
Which transition metal exhibits variable oxidation states and is commonly used as a catalyst in the Contact process for H₂SO₄ manufacture?
Practice 4easy
Which of the following d-block elements has the electronic configuration [Ar] 3d⁵ 4s² in its ground state?
Practice 5easy
What is the primary reason lanthanides are called 'rare earths' despite their relatively high abundance in Earth's crust?
Practice 6medium
Which f-block element has the electronic configuration [Rn] 5f⁶ 7s²?
Practice 7medium
Which of the following transition metals does NOT form stable +3 oxidation state in aqueous solution?
Practice 8medium
The lanthanide contraction results in similar ionic radii for pairs of elements. Which pair demonstrates this effect most clearly?
Practice 9medium
Which of the following d-block elements exhibits the maximum number of oxidation states?
Practice 10medium
The electronic configuration of Cu²⁺ ion is:
Practice 11medium
Which lanthanide element is commonly used in nuclear reactors as a neutron absorber?
Practice 12medium
Among the first-row transition metals, which element has the highest melting point?
Practice 13medium
The colour of [CuCl₄]²⁻ complex ion is yellow-green. This is due to:
Practice 14hard
In the complex [CoF₆]³⁻, cobalt exhibits an oxidation state of +3. Given that F⁻ is a weak field ligand, what is the expected electronic configuration and magnetic behavior of this complex?
Practice 15hard
The lanthanide contraction causes the ionic radii of lanthanides to decrease across the series. Which of the following statements correctly explains the consequence of lanthanide contraction?
Practice 16hard
Which of the following d-block elements exhibits the highest number of oxidation states in its compounds?