Which of the following is an element present
in the d-block, but not a transition element
1) cd 2) Cu 3) Ca 4) Cr
Answers
The transition elements or transition metals occupy the short columns in the center of the periodic table, between Group 2A and Group 3A. They are sometimes called the d-block elements, since in this region the d-orbitals are being filled in, and are also referred to as B-group elements since in most numbering systems of the columns on the periodic table the numerals of these groups are followed by the letter B. The period 4 transition metals are scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn). The period 5 transition metals are yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), and cadmium (Cd). The period 6 transition metals are lanthanum (La), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), and mercury (Hg). The period 7 transition metals are the naturally-occurring actinium (Ac), and the artificially produced elements rutherfordium (Rf), dubnium (Db), seaborgium (Sg), bohrium (Bh), hassium (Hs), meitnerium (Mt), darmstadtium (Ds), roentgenium (Rg), and the as-yet unnamed ununbiium (Uub).
The elements which follow lanthanum (Z=57) and actinium (Z=89) are called the lanthanides and actinides, respectively, and together are known as the inner transition elements.
In the transition metals, the five d orbitals are being filled in, and the elements in general have electron configurations of (n-1)d1-10 ns2, although there are some exceptions when electrons are shuffled around to produce half-filled or filled d subshells. Many of the transition metals can lose two or three electrons, forming cations with charges of 2+ or 3+, but there are some which form 1+ charges, and some which form much higher charges.
All of the transition metals in their elemental forms are malleable and ductile (except for mercury, which is a liquid at room temperature), and are good conductors of heat and electricity. Many of the transition metal ions have characteristic colors associated with them, and many have biological and industrial significance.