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In the periodic table of the elements, each column is a group. In chemistry, a group (also known as a family) [1] is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered.
The periodic table of the chemical elements.The columns represent the groups.Groups 1, 2 and 13 to 18 constitute the main group. Sometimes groups 3 and 12, as well as the lanthanides and actinides (the two rows at the bottom), are also included in the main group.
However, in terms of its nuclear structure it belongs to the s-block, and is therefore sometimes classified as a group 2 element, or simultaneously both 2 and 18. Hydrogen readily loses and gains an electron, and so behaves chemically as both a group 1 and a group 17 element.
This can hold up to two electrons. The second shell similarly contains a 2s orbital, and it also contains three dumbbell-shaped 2p orbitals, and can thus fill up to eight electrons (2×1 + 2×3 = 8). The third shell contains one 3s orbital, three 3p orbitals, and five 3d orbitals, and thus has a capacity of 2×1 + 2×3 + 2×5 = 18.
Radioactive: 40 K, t 1/2 1.25 × 10 9 years; 87 Rb, t 1/2 4.9 × 10 10 years; 223 Fr, t 1/2 22.0 min. All the alkali metals have odd atomic numbers; hence, their isotopes must be either odd–odd (both proton and neutron number are odd) or odd–even ( proton number is odd, but neutron number is even).
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). [1] The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. [2]
Elements in groups 1–2 or 13–18, excluding hydrogen * Transition elements are sometimes referred to as transition metals † Although the heavier elements of groups 15 (Mc), 16 (Lv), 17 (Ts) and 18 (Og) have been notionally assigned to the indicated groups their chemical properties have not yet been experimentally confirmed.
Their general valence configuration is ns 1–2. Helium is an s-element, but nearly always finds its place to the far right in group 18, above the p-element neon. Each row of the table has two s-elements. The metals of the s-block (from the second period onwards) are mostly soft and have generally low melting and boiling points. Most impart ...