A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). A Markov chain is a discrete random process with the property that the next state depends only on the current state (wikipedia). So $P(X_n | X_1, X_2, \ldots X_n-1) = P(X_n | X_{n-1})$.
Some people find molecules and compounds confusing. Here's how to remember the difference. If you join two different chemical elements together, you can often make a completely new substance. Glue two atoms of hydrogen to an atom of oxygen and you'll make a single molecule of water.
Atoms have the  same number of protons and electrons, â¦ because otherwise, you would  have an ion.   A molecule consists of two or more atoms bonded together.    Atoms are single units of elements.   Molecules are agglomerations of two or more atoms  (of the same or different elements). A molecule is the smallest  particle of a chemical compound. Molecules are formed by atoms in a  multitude of different arrangements.   - Most atmospheric oxygen forms diatomic molecules (O2),  but also ozone (O3)   - One molecule of water has one atom of hydrogen and two atoms of  oxygen. So-called heavy water contains deuterium, which is hydrogen  that has neutrons.