Transition metals are often paramagnetic owing to-
Transition elements containing one or more unpaired electrons show paramagnetic behavior where the effects of individual electrons are not mutually compensated. The magnetic moment due to unpaired electron spins are aligned parallel to the external magnetic field more effectively.
Electron affinity of noble gases is -
Large atoms have low ionization energy and low electron affinity. Therefore, they tend to lose electrons and do not tend to gain electrons. Any electrons added to a noble gas would have to be the first electron in a new (larger) energy level. This causes the noble gases to have essentially zero electron affinity.
All the elements in a group in the periodic table have the same-
The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons. They are the electrons involved in chemical bonds with other elements.
“Which elements are arranged in increasing order of atomic weight, every eighth element has properties similar to the first”. This law had been given by-
John Alexander Reina Newlands (26 November 1837 – 29 July 1898) was a British chemist. Newlands was the first person to devise a periodic table of chemical elements arranged in order of their relative atomic masses.
Which of the following gases is heavier than oxygen?
For oxygen, a molecule consists of two oxygen atoms, and has a weight of 2 x 16 = 32. For carbon dioxide, there is one carbon atom (weight 12) and two oxygen atoms (mass 16 x 2) for a total of 44. This means that carbon dioxide should be about 44/32 = 1.375 times (ideally) as heavy as an equivalent volume of oxygen. In reality, carbon dioxide is 1.383 times as heavy as oxygen. Even after solidification carbon dioxide is slightly heavier than similar volume of solid oxygen.
All isotopes of the same element have _________.
All isotopes of the same element have the same atomic number but different atomic masses.
What are the main components of Brass Alloy?
Brass is a metallic alloy that is made of copper and zinc. Brass is commonly used for decorative purposes primarily because of its resemblance to gold. It is also a commonly used to make musical instruments due to its high workability and durability.
Which of the following is a chemical formula of quicklime?
CaO is a chemical formula of quicklime
The plants receive Nitrogen in form of:
Ammonium (NH4+) and nitrate (NO3-) are the predominant inorganic forms of nitrogen in the soil. Plants normally use nitrogen in the form of nitrate.
What is formed when Magnesium is burnt?
When the magnesium metal burns it reacts with oxygen found in the air to form Magnesium Oxide. Oxygen and magnesium combine in a chemical reaction to form this compound. After it burns, it forms a white ash of the magnesium oxide.
Which of the following statements regarding heavy water are correct?
I. It is extensively used as a moderator in nuclear reactors.
II. It cannot be used in exchange reaction to study reaction mechanism.
III. Viscosity of heavy water is relatively smaller than that of ordinary water.
IV. The dielectric constant of heavy water is smaller than that of ordinary water. Select the correct answer using the codes given below:
Statement I: Oxygen gas is easily produced at a faster rate by heating a mixture of potassium chlorate and manganese dioxide than heating potassium chlorate alone.
Statement II: Manganese dioxide acts as a negative catalyst.
To weld metals together, high temperature is required. Such a high temperature is obtained by burning
Graphite is a much better conductor of heat and electricity than diamond. This is due to the fact that each carbon atom in graphite
Which one of the following elements will not react with dilute HCl to produce H₂ ?
Which one of the following oxides of nitrogen is known as ‘anhydride’ of nitric acid?
Statement I: Petroleum is a mixture of many different hydrocarbons of different densities.
Statement II: The grade of petroleum depends mainly on the relative proportion of the different hydrocarbons. Codes
Which of the following carbon compounds will not give a sooty flame?
Which of the following is water gas ?
Water gas is the mixture of hydrogen and carbon monoxide. Water gas is obtained by action of steam on red-hot coke.
A glass vessel is filled with water up to the brim and a lid is fixed to it tightly. Then it is kept inside a freezer for hours. What is expected to happen?