A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
Halogens are the group 17 elements of the periodic table. The term ‘halogen’ means ‘salt-producing’, hence the name halogens as they possess the tendency to form salts after reacting to metals. It generally has five elements:
These are all naturally occurring halogens but Tennessine (Ts) is an artificially created halogen.
Halogens are highly reactive elements and are highly electronegative. They have a high tendency to react with metals to form salts. They are also known as Group 17 elements. They have 7 electrons in their outer shell with a configuration of (ns2 np5). Fluorine being the first halogen in group 17, is highly reactive. Astatine is a halogen because of its resemblance with iodine despite it being radioactive.
The general electronic configuration for group 17 elements is ns2np5. This configuration clearly shows that they have 7 electrons in their valence shell. They require one more electron to complete their octet and achieve noble gas configuration.