Class 10 Science Chapter 5 MCQ

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

Non-metals can form acidic oxides in general. Non-metals have 4 to 8 electrons in the outermost shell. The electronic configuration of given elements are (a) i.e. 7 = 2, 5 (b) i.e., 3 = 2, 1 (c) i.e., 12 = 2, 8, 2 (d) i.e., 19 = 2, 8, 8, 1. So, element with atomic number 7 (electronic configuration 2, 5) with is non-metal (N) and it will form an acidic oxide. Rest three elements atomic numbers, 3 (Li), 12 (Mg) and 19 (K) are metals and hence form basic oxides.

The elements boron (B), silicon (Si) and germanium (Ge) are metalloids. In the periodic table, metals have been separated from non-metals by some elements called “metalloids” which are placed diagonally in the periodic table. These metalloids are B, Si, Ge, As (arsenic), Sb (antimony), Te (tellurium) and (Po) polonium.

Here, all the statements are incorrect. Hence, your answer will be option [D]. Explanation: In option [A], In Mendeleev’s periodic table, the elements are arranged on the basis of their atomic masses and also on the similarity of chemical properties, whereas the modern periodic table is based on the atomic numbers of elements. In option [B]: Dobereiner’s triads also exist in the columns of Newlands’ classification of elements based on the law of octaves. In option [C]: The periodic table is a chart of elements prepared in such a way that the elements having similar properties occur in the same vertical column or group. It is called periodic because the elements having similar properties are repeated after certain intervals or periods; and it is called a table because the elements are arranged in the tabular form.

Gallium has a valency of 3. Hence, it forms an oxide having molecular formula E2O3. In other options, valency of E is not 3. Note: Eka-Aluminium (first element after Aluminium) i.e. gallium lies in group III of the Mendeleev’s periodic table.

Here, all the statements are incorrect. Hence, your answer will be option [D].

Li, O, C, Be, F belong to same period i.e. 2nd period. In a period on moving from left to right, non-metallic character increases. Thus, the order of increasing non-metallic character is: Li < Be < C < O < F.

Due to large positive charge on the nucleus, the electrons are pulled in more close to the nucleus and the size of the atom decreases. However, the size of atom of an inert gas is bigger than that of the preceding halogen atom. The greater size of the inert gas atom in a period is due to the structural stability of its outermost shell consisting of an octet of electrons. Note: As we move from left to right in a period, the atomic number of elements increases which means that the number of protons and electrons in the atoms increases (the extra electrons being added to the same shell.

Isotopes are the atoms of the same element having same atomic number and hence, similar chemical properties but different atomic masses. Note: All the isotopes of an element have the same atomic number. Therefore, they can be placed at one place in the same group of the periodic table. Chemical properties depend on the electronic configuration of the element i.e. atomic number of the element.

In the modern periodic law, the electronic configuration of silicon is 2, 8, 4.

Na and K are in the same group and K is below than Na, so K will have higher atomic radius i.e., K > Na. In a period on moving from left to right, atomic radius decreases. Since, K and Ca are in the same period and K is in 1 group and Ca is in 2 group, so atomic radius of K will be more than Ca, i.e., K> Ca. Also, Na and Mg are in the same period, but Na belongs to 1 group and Mg belongs to 2 group, so atomic radius of Na is more than Mg, i.e., Na > Mg. Thus, if we take all these together we get K > Na > Mg and K > Ca> Mg. Hence, we can say the atomic radius of K largest. Note: Atomic radii increases on moving down the group as new shell of electrons is added at each succeeding element.

As we move from left to right in a period, the atomic number of each succeeding element increases by 1. So, the electrons are attracted close to the nucleus and hence, the atomic size decreases, along a period from left to right. Therefore, the increasing order of radii is F, O, N as atomic number of F, O and N are 9, 8 and 7 respectively. Due to which F belongs to 17th group. O belongs to 16th group and N belongs to 15th group. Note: Atomic radii is the distance between the centre of the nucleus and the outermost shell which contains electrons in an isolated system.

Here, all the statements are correct. Hence, your answer will be option [D].

Constituent of all organic compounds is carbon. It belongs to group 14.

The elements with atomic numbers 57 to 71 are called lanthanide series (because their first element is lanthanum). And the elements with atomic numbers 89 to 103 are called actinide series (because their first member is actinium).

Here, all the statements are correct. Hence, your answer will be option [D].

The first period starts with hydrogen and ends with noble gas helium. All other periods start with alkali metals like lithium, sodium, potassium, etc., and end with noble gases like neon, argon, krypton, etc.

2nd period contains elements with atomic number 3(Li), 7(N), 10(Ne). Since, 2nd period has elements having atomic number 3 to 10. Note: The number of elements in any period is fixed by the maximum number of electrons that can be accommodated in that particular shell. The maximum number of electrons that can be accommodated in any shell is given by the formula 2n2 where, n is the number of the given shell starting from the nucleus.

Modern Periodic table has 18 vertical columns, known as groups and 7 horizontal rows, known as periods.

Here, all the statements are correct. Hence, your answer will be option [D].

The groups 1 and 2, and 13 to 17 contain the normal elements (typical elements or representative elements). Group 18 elements are known as noble gases or inert gases. They are helium, neon, argon, krypton, etc. All the noble gases have 8 electrons in their outermost shells (except helium which has only 2 electrons in the K valence shell). Thus, the valence shells of all the noble gases are completely filled with electrons.

Mendeleev’s left some gaps in the periodic table for those elements which were not known at that time. Germanium element found a place in the periodic table later and Mendeleev’s predictions were found to be remarkably correct.

According to Mendeleev’s periodic law, the elements were arranged in the periodic table in the order of increasing atomic masses. Note: Mendeleev’s periodic law states that, the physical and chemical properties of elements are a periodic function of their atomic masses.

Newlands’ law of octaves was applicable only to lighter elements having atomic masses upto 40 u i.e., upto calcium. After calcium, every eighth element did not possess properties similar to that of the first element.