Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.
In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.
The subscriot 2 means that in the formula there are two parts of K, and the subscript 1 (implicit) for S, indicates that there is one part of S.
This is, the formula gives the ratio of the elements K and S in the compound, which is:
2 atoms of K : 1 atom of S.
Answer: there are 2 atoms of K and 1 atom of S in a molecule of K2S.
Answer and Explanation:
BINARY COMPOUND: A binary compound is that compound which is made up of exactly two elements there are a lot binary compound present for example :
etc
TERNARY COMPOUND : A ternary compound is that compound which is made up of exactly three elements there are a lot binary compound present for example : 
etc
Hear n = 1000 to n = 2 pairs of quantum states of hydrogen has the biggest energy difference between the states
A quantum state is a mathematical concept used in quantum physics that gives a probability distribution for the results of each potential experiment on a system. All that can be predicted about the behaviour of the system is exhausted by knowledge of the quantum state and the laws governing the system's evolution across time. Another quantum state is a combination of quantum states. All other quantum states are known as mixed quantum states, whereas pure quantum states are those that cannot be described as a combination of other states. A ray in a Hilbert space over the complex numbers can represent a pure quantum state, but density matrices, which are positive semidefinite operators acting on Hilbert spaces, can represent mixed states.To know more about ray, visit to: -brainly.com/question/17491571#SPJ4
