FreeNotes
Alkali metals, found in Group 1 of the periodic table, are highly reactive, soft metals with low melting points. They have one electron in their outermost shell, which they easily lose to form positive ions (cations). Examples include lithium (Li), sodium (Na), and potassium (K). Halogens, found in Group 17, are highly reactive nonmetals with … Read more
Mendeleev’s periodic law stated that the properties of elements are a periodic function of their atomic masses. By arranging elements in order of increasing atomic mass, Mendeleev noticed that elements with similar properties occurred at regular intervals. He also predicted the existence and properties of elements that had not yet been discovered, based on gaps … Read more
In the periodic table, atomic size decreases as you move across a period from left to right. This happens because as the nuclear charge increases, electrons are pulled closer to the nucleus, reducing the size of the atom. For example, the atomic radius of sodium (Na) is larger than that of chlorine (Cl). Ionization energy, … Read more
A period refers to a horizontal row in the periodic table where elements have the same number of electron shells. As you move across a period, the atomic number increases, and properties such as ionization energy and electronegativity change. A group, on the other hand, refers to a vertical column where elements share similar chemical … Read more
Periodicity refers to the recurring trends or patterns in the properties of elements when arranged in order of increasing atomic number. These trends include atomic radius, ionization energy, electron affinity, and electronegativity. The periodic repetition of these properties is due to the regular arrangement of electrons in energy levels or shells as you move across … Read more
Alkali metals are highly reactive because they have only one electron in their outermost shell, which they can easily lose to achieve a stable noble gas configuration. This makes alkali metals very eager to react with other elements, especially halogens, to form stable compounds. The reactivity increases down the group because the outer electron is … Read more
Noble gases have high ionization energies because they possess a stable electron configuration with a full outer shell. This stability makes it difficult to remove an electron from the outermost energy level. The strong attraction between the positively charged nucleus and the tightly bound electrons requires a considerable amount of energy to overcome, thus giving … Read more
The atomic radius decreases across a period from left to right due to the increasing nuclear charge (the number of protons in the nucleus). As more protons are added, the positive charge of the nucleus attracts the electrons more strongly, pulling them closer to the nucleus. Although electrons are added to the same energy level, … Read more
(a) 1s², 2s¹: Block: s-block, Group: 1, Period: 2(b) 1s², 2s², 2p⁶: Block: p-block, Group: 18, Period: 2(c) 1s², 2s², 2p⁶, 3s¹: Block: s-block, Group: 1, Period: 3(d) 1s¹: Block: s-block, Group: 1, Period: 1 Related Questions: Arrange the elements in each of the following in order of decreasing shielding effect: Specify which of the … Read more
(a) An element present in period 3 of Group VA: Arsenic (As) – 3s² 3p³(b) An element present in period 2 of Group VIA: Oxygen (O) – 2s² 2p⁴ Related Questions: Write the valence shell electronic configuration for the following groups: Write the valence shell electronic configuration of an element present in the 3rd period … Read more