valence of 8

Question: On what basis is Potassium (z = 19) placed in 4 th period and 1 st group? Answer: The electronic configuration of potassium is 2, 8, 8, 1. It has four shells so it belongs to the 4 th period. The 4 th period has elements with the 4 th shell being filled..

Al, Ga, In and Tl react with halogens to give binary halides. All the halides of group 13 elements are known except Tl(III) iodide. The fluorides are ionic and have high melting points. The chlorides, bromides and iodides are essentially covalent compounds with low melting points. The boron trihal..

. They consist of metals. 7. The Zero group consists of 'Noble gases'. 8. There are 7 horizontal rows in the periodic table. These are called the periods. 9. In a period, the number of valence shell remains the same for all elements. However, the number of electrons in the ..

A chlorine atom is extremely reactive. It cannot exist freely as it does not have a stable electronic configuration. Chlorine does not exist as single atom but as a diatomic molecule. A single covalent bond is formed between two chlorine atoms. Each chlorine atom has an electronic configuratio..

Symbol O Molecular formula O 2 Atomic number 8 Mass number 16 Atomic mass 16 Molecular mass 32 Electronic configuration 2,6 Valency -2 Isotopes 16 17 ..

. They are generally brittle. Electronic configuration They usually have 1, 2 or 3 electrons in their valence shell. The greater the number of shells and lesser the number of valence electrons, the greater is the reactivity of the metal. They usually have 4, 5, 6 or 7 electrons ..

Third Row Elements - The third row elements are from sodium to argon. The build up of these eight elements proceeds exactly in the same manner as discussed above. Here 3s- and 3p-orbitals are filled in place of 2s- and 2p-orbitals as has been done in case of Li to Ne. For e.g., the electr..

. According to Mendeleev's periodic law, the physical and chemical properties of elements are periodic functions of their atomic mass Mendeleev was able to predict the existence of undiscovered elements like Ga, Sc and Ge Mendeleev corrected the atomic masses of a few elements on the basis of their..

Electronic Nature of Metals and Non-metals - We are familiar with the fact that the atoms of all elements, except noble gases, have an incomplete outermost shell. Consequently, most elements are reactive and they try to achieve the stability of the noble or inert gases by electron transfer or by el..

Boron - Boron (B) is the first member of group 13 of the periodic table and is the only non-metal of this group. It has an electronic configuration of 1s 2 2s 2 2p 1 with only three electrons in its valence shell. Dissimilarities of boron with other elements of this group are: Boron is a ..