1) Atoms combine in the ration of small whole numbers to form compounds.
2) The relative number and kinds of atoms are constant in a given compound.
Please explain these 2 laws of Dalton's theory.
Atoms of different elements combine in small whole number ratios to form compounds.
The above statement means that atoms which belong to different elements will combine with each other only in simple whole number terms and not in fractions. For example, in water (H2O), two atoms of hydrogen combine with one atom of oxygen to form a molecule of water. Similarly in carbon dioxide (CO2), two atoms of oxygen combine with one atom of carbon to form a molecule of carbon dioxide. In none of the above cases, we find that one atom is combining in fractions with the other atom. For example, it is not the case that 0.5 atom of oxygen combine with one atom of hydrogen.
In a given compound, the relative number and types of atoms are constant.
The above statement means that a given compound, whatever be its source will always contain the same number of atoms of different elements (that form the compound). In other words, the number of atoms of different elements in a compound is fixed and does not vary. We can say that the composition of a compound is fixed as same atoms will always combine in the same ratio.
Thus a molecule of water will always have 2 atoms of hydrogen and one atom of oxygen.
2. Atoms combine to form molecules
Energy flues life’s activities
Chemical bonds link atoms to form molecules
Functions in life
Part of water and most organic molecules; also molecular oxygen
The backbone of all organic molecules
Part of all organic molecules and of water
Component of proteins and nucleic acids
Constituent of bone; also essential for the action of nerves and muscles
Part of cell membranes and of energy storage molecules; also a constituent of bone
Important in nerve action
Structural component of most proteins
The primary ion in body fluids, also important for nerve action
Component of digestive acid; also a major ion in body fluids
Important for the action of certain enzymes and for muscle contraction
A constituent of hemoglobin, the oxygen-carrying molecule