Beginner Level; Multiple Choice Questions On Chemistry For 11th Grade

Atomic mass number is another name for atomic weight. It represents the total number of protons and neutrons in the nucleus of an atom. Atomic number, on the other hand, represents the number of protons in an atom. Atomic density and atomic kilograms are not related to the concept of atomic weight.

Molecules are formed by the bonding of two or more atoms to each other. Atoms combine with each other through chemical bonds to form molecules, which are the smallest units of a compound that retain its chemical properties. This bonding can occur through various types of chemical interactions, such as covalent bonds, ionic bonds, or metallic bonds. Through these bonds, atoms share, transfer, or pool their electrons to achieve a stable configuration and form a molecule. Therefore, the correct answer is "Bonding of two or more atoms to each other."

Dmitri Mendeleev was the first person to organize elements into the periodic table. He developed the table based on the properties of elements and their atomic weights. Mendeleev's periodic table arranged elements in order of increasing atomic weight and grouped elements with similar properties together. His work laid the foundation for the modern periodic table that we use today.

A covalent bond is formed when atoms share electrons. In this type of bond, two or more atoms share their outermost electrons in order to achieve a stable electron configuration. This sharing of electrons creates a strong bond between the atoms, holding them together in a molecule. Unlike in ionic bonds, where electrons are transferred from one atom to another, covalent bonds involve the sharing of electrons. This allows atoms to fill their outermost electron shells and attain a more stable state. Therefore, the correct answer is "When atom share electrons."

Isotonic bonds are not a type of chemical bond. Ionic bonds occur between ions with opposite charges, where one atom gives up an electron to another atom. Covalent bonds occur when atoms share electrons. Metallic bonds occur between metal atoms and involve the sharing of electrons in a "sea" of delocalized electrons. Isotonic bonds, on the other hand, do not exist in chemistry.

The correct answer is He (Helium) because it is an element and not a molecule. A molecule is formed when two or more atoms chemically bond together, whereas He is a noble gas that exists as individual atoms and does not form bonds with other atoms. H2, C6H12O6, and NaCl are all examples of molecules as they consist of two or more atoms bonded together.

Nucleons consist of protons plus neutrons. Protons are positively charged particles found in the nucleus of an atom, while neutrons are neutral particles also located in the nucleus. Together, protons and neutrons form the majority of an atom's mass and are collectively known as nucleons. Electrons, on the other hand, are negatively charged particles that orbit around the nucleus, and ions are atoms or molecules that have gained or lost electrons, resulting in a net electrical charge. Neurons, which are cells in the nervous system, are not involved in the composition of nucleons.

The name given to elements moving from top to bottom is "Group". In the periodic table, elements are arranged in rows called periods and columns called groups. Elements within the same group have similar properties and exhibit similar chemical behavior. As we move down a group, the number of energy levels or shells increases, resulting in the addition of more electrons. Therefore, the elements in a group have the same number of valence electrons, which contributes to their similar properties.

The atomic number of an element is determined by the number of protons in its nucleus. Protons are positively charged particles found in the nucleus of an atom. Each element has a unique number of protons, which defines its atomic number. The number of electrons and neutrons in an atom can vary, but the number of protons remains constant for a specific element. Therefore, the correct answer is the number of protons.

In 1869, the periodic table was first organized. This date marks the publication of Dmitri Mendeleev's periodic table, which arranged the elements based on their atomic mass and chemical properties. Mendeleev's work was a significant milestone in the field of chemistry, as it provided a systematic way to classify and understand the elements.