| TERMS | DEFINITIONS |
| Matter | Anything that occupies space and has mass is called |
| Mass | The amount of matter in an object is called Mass |
| Element | The chemical substances that in ordinary chemical
reactions cannot break down into simpler units are called element. |
| fitom | The smallest part of an element that can enter into a chemical reaction is called atom. | ||
| , | Atomic
number |
The atomic number of an element is the number of
protons in the nucleus of one of its atoms. |
|
| Atomic
mass |
The atomic mass is equal to the number of neutrons and protons in the atom’s nucleus. | ||
| Isotopes | The different forms with the same atomic number but different atomic masses are isotopes. | ||
| E | shell
ergy level or |
The electrons of an atom are distributed around its
nucleus in orbital called energy-level shells or clouds of electrons . |
|
| Compound | A compound is composed of atoms of two or more elements chemically united in fixed proportions. | ||
| Covalent
bond |
The chemical bond formed by the sharing of electrons is called covalent bond. | ||
| Hydrogen
bonding , |
The electrostatic force of attraction between
electronegative atom and partially positively charged |
||
| Hydrogen
bonding |
The electrostatic force of attraction between
electronegative atom and partially positively charged |
||
| Electrolytes | A substance that conducts electricity in solution form is called electrolytes. | ||
| Bu | er | The substance which resists change in pH is called buffer. | |
| Ca | tohydrates | Polyhydroxy aldehyde or ketones are called carbohydrate. | |
| Lipids | Lipids are nonpolar organic molecules that are insoluble in polar water but soluble in nonpolar organic solvents like
ether, alcohol, and chloroform. • |
||
| Fatty | acids | Fatty acids contain long hydrocarbon chains bonded to,. carboxyl (COOH) groups. | |
| Fats | Fats are esters of fatty acids and glycerol. | ||
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