Relative Sizes of Atom of Hydrogen , water molecule , molecule of haemoglobin ,Grain of sand , Ant , water melon
Atomic radius is measured in nanometres. 1/10 9 m = 1 nm 1 m = 109 nm
MOLECULES OF ELEMENTS
The molecules of an element are constituted by the same type of atoms. Molecules of many elements, such as argon (Ar), helium (He) etc.are made up of only one atom of that element.But this is not the case with most of the nonmetals. For example, a molecule of oxygen consists of two atoms of oxygen …
What is a Molecule ?
A molecule is in general a group of two or more atoms that are chemically bonded together, that is, tightly held together by attractive forces. A molecule can be defined as the smallest particle of an element or a compound that is capable of an independent existence and shows all the properties of that substance. …
HOW DO ATOMS EXIST ?
Atoms of most elements are not able to exist independently. Atoms form molecules and ions. These molecules or ions aggregate in large numbers to form the matter that we can see, feel or touch.
ATOMIC MASS
The most remarkable concept that Dalton’s atomic theory proposed was that of the atomic mass. According to him, each element had acharacteristic atomic mass. The theory could explain the law of constant proportions so well that scientists were prompted to measure theatomic mass of an atom. Since determining the mass of an individual atom was …
WHAT ARE THE MODERN DAY SYMBOLS OF ATOMS OF DIFFERENT ELEMENTS?
Dalton was the first scientist to use the symbols for elements in a very specific sense.When he used a symbol for an element he also meant a definite quantity of that element, that is, one atom of that element. Berzilius suggested that the symbols of elements be made from one or two letters of the …
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What is an Atom?
Atoms are defined as “the basic building blocks of matter”. Atom is the smallest constituent unit of matter that possess the properties of the chemical element. Atoms don’t exist independently, instead, they form ions and molecules, They can take part in the chemical reactions.. An atom is a particle of matter that uniquely defines a chemical element. …
Dalton’s atomic theory
According to Dalton’s atomic theory, all matter, whether an element, a compound or a mixture is composed of small particles called atoms. The postulates of this theory may be stated as follows: (i) All matter is made of very tiny particles called atoms, which participate in chemical reactions.(ii) Atoms are indivisible particles, which cannot be …
LAW OF CONSTANT PROPORTIONS
Lavoisier, along with other scientists, noted that many compounds were composed of two or more elements and each such compound had the same elements in the same proportions, irrespective of where the compound came from or who prepared it. In a compound such as water, the ratio of the mass of hydrogen to the mass …
LAW OF CONSERVATION OF MASS
Law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction., The mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. If we account for all reactants and products in a chemical reaction, …