Electrons are easily released and transferred from one atom to another by friction-glass and silk, wax and wool, heat-generating voltage by collision of bumpy metals, chemical reactions-oxidation.

Molecular weight of oxygen is 31.99 and atomic weight is 15.88 and its atomicity is approximately 2.

Arsenic (As) has an atomic number of 33 that indicates, it has 33 protons in its nucleus and 33 electrons around the electron while it is uncharged.

The combination of two nuclides is called isotope if they have same proton number-Z, but different neutron (mass) number-N. Example: Carbon-12, Carbon-14.

A dry cell is an electric battery comprises of zinc anode (cylindrical drum-acts as negative electrode), a piece of carbon cathode (central rod-acts as positive electrode), electrolyte (ammonium chloride in the form of paste) and the vacuum is filled up with manganese dioxide. 

Hydrogen is the lightest and simplest element on earth ever found. The atomic number and mass number of hydrogen is the same.

Atoms are electrically neutral because they have equal numbers of protons (positively charged) and electrons (negatively charged). If an atom gains or loses one or more electrons, it becomes an ion. If it gains one or more electrons, it now carries a net negative charge, and is thus "anionic."

A physical change involves a change in physical properties, such as melting, transition to a gas and change of strength. For burning candle, wax melts which is known as physical change. Also the wax near the flame burns and generates CO2, light and heat which is a chemical change. Hence, burning of candle is a physical as well as chemical change.

A chemical change occurs when the substance's composition is changed. Cooking rice is a chemical change because during this process changes in the chemical properties of rice occur and we get a new substance that is cooked rice.

Oxidation reaction is a chemical process. It is defined as a process that occurs when a chemical species gains oxygen or loses hydrogen. In electronic terms loss of electrons is called oxidation.