![]() They produce fluorescence on a zinc sulphide screen. They cause a greenish-yellow fluorescence on a soda-glass screen. They travel from the anode to the cathode. They travel from the cathode to the anode. How do cathode rays differ from anode rays? These rays were named positive rays or anode rays. He called these rays as canal rays since these rays passed through the holes or canals in the cathode. In discharge tube experiment, Goldstein noticed another set of rays travelling in a direction opposite to that of the cathode rays i.e., from anode towards cathode, when perforated cathode was used in the discharge tube. Why were anode rays also called as 'canal rays'? When a beam of cathode rays is made to fall upon hard metallic targets like tungsten, X-rays are produced. Question 5Ĭathode rays are negatively charged as they are made of negatively charged particles.Īnode rays are positively charged as they are made of positively charged particles. What are the cathode rays? How are these rays formed?Ĭathode rays are a stream of electrons that travel from the negatively charged electrode (the cathode) to the positively charged electrode (the anode) in a discharge tube.įormation of cathode rays - When a high voltage (10,000 volts) charge from an induction coil is applied to tubes filled with gases at very low pressure (0.01 mm of Hg), the gases become good conductors of electricity and begin to flow from cathode to anode in the form of rays which are called cathode rays. It is formed by removing 2 electrons from helium atom. Atoms are the smallest units of matter that can take part in a chemical reaction.Īn α (alpha) particle is a doubly charged helium ion (He 2+) containing two protons and two neutrons.Atoms of one element combine with atoms of another element in a simple ratio to form molecules of compounds. ![]() Atoms of an element combine in small numbers to form molecules.The atoms of an element are alike in all respects, but they differ from the atoms of other elements.Atoms can neither be created nor be destroyed.Matter consists of very small and indivisible particles called atoms.Main postulates of Dalton's atomic theory are: The existence of different types of matter is considered to be due to different types of atoms constituting them. He considered atoms as indivisible particles that are the fundamental building blocks of matter. John Dalton gave the first scientific theory about the structure of matter. (b) Democritus called the paramanu an atom, which is derived from the Greek word atomos, meaning indivisible. Each one of them exhibits specific properties. A paramanus does not exist in free state, rather it combines with other paramanus to form a bigger particle called anu, now known as molecule. According to him, matter consisted of indestructible minute particles called paramanus, now called atoms. (a) The idea of the smallest unit of matter was given by Maharshi Kanada. What is the contribution of the following in Atomic structure?
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |