A Genius Dmitri Ivanovich Mendeleev

DMITRI IVANOVICH MENDELEEV

Dmitri Ivanovich Mendeleev was born in Tobolsk (Siberia), on 8 February 1934. After his early education, he joined university due to effort of his aged mother. He received a master degree in chemistry in 1856 and doctoral degree in 1865. He was appointed professor of general chemistry in 1867, at university of St. Petersburg. In 1869 he proposed a famous “periodic law” and constructed a periodic table of elements. In this table, he placed certain elements at specific places in accordance with their properties. He also predicted properties of some undiscovered elements.

Mendeleev was a versatile genius. He was interested in many areas of science. He worked a lot on natural resources too. In 1890, he resigned his professorship, and appointed the director of the bureau of weight and measures. Mendeleev dedicated all his work to his mother. To name the element with atomic number 101 mendelevium was proposed to honour Mendeleev by American scientist Glenn T Seaborg, the discoverer of the element. Mendeleev died in February 1907.

Comments

Working of the heart

WORKING OF HEART Blood from different parts of the body comes to right atrium, when it expands. Blood is brought from upper part of the body through superior vena cava and from lower part of the body through inferior vena cava. When right atrium contracts, the blood goes to right ventricle. The atrioventricular aperture is closed by a valve after blood transfer. Valves prevent backflow of blood when the atria or ventricle contracts. When the right ventricle contracts, blood forced out to the lungs for oxygenation through pulmonary artery, guarded by another valve. In lungs the exchange of gases takes place, blood give off carbon dioxide and takes in oxygen from lungs. Pulmonary vein brings oxygenated blood from lungs to the left atrium, as it relaxes. When the left atrium contract, the blood is transferred to left ventricle, which expands. The aperture be...

Molotov Cocktail (Petrol Bomb)

MOLOTOV COCKTAIL (PETROL BOMB) INTRODUCTION Molotov cocktail is term for the simple incendiary weapon. It is also known as petrol bomb, fire bomb and benzine torch. They are relatively easy to make and may be used by irregular paramilitary forces and rioters. These bombs are also used to commit arson. These bombs are first used in Spanish civil war between July 1936 to April 1939, before they became to known as “Molotov cocktail”. MECHANISM A Molotov cocktail consists of a glass bottle apart filled with flammable liquids. The liquid will typically be gasoline, alcohol, menthol, or ethanol. The mouth of bottle is closed with a cork or other type of tight sealing made up of glass, plastic, or rubber. A cloth rag is fixed securely around the bottle mouth. The weapon is used by first soaking the rag in flammable liquid immediately before use, lighting the rag and throw the bottle at the target....

Chemical Bond-An Introduction

CHEMICAL BOND- AN INTRODUCTION Octet:- Eight electrons in the outermost shell of an atom is said to form an octet. Duplet:- Two electrons in the outermost shell of an atom just like helium constitute a duplet. Q.1. why chemical reaction takes place? All elements want to achieve a stable configuration to their nearest noble gas. This leads to chemical reaction. Q.2. what types of way an element follows to achieve a stable configuration during chemical combination? The following ways are follows by an element to achieve a stable configuration during chemical combination:- 1. By transfer of valence electrons from one atom to another. 2. By sharing of valence electrons between two combining atoms. Chemical bonds:- The attractive force which holds together two atoms, two molecules, two ions or a combination of these is...

Bright Mind

Search This Blog