Science · X-Factor Notes
Inorganic Chemistry revision notes for UPPCS Prelims.
13 revision facts
| Concept | What to remember | Asked in UPPCS |
|---|---|---|
| Mendeleev's Periodic Law | The physical and chemical properties of the elements are a periodic function of their atomic mass. | - |
| Modern Periodic Law (Moseley) | The chemical and physical properties of elements are a periodic function of their atomic number. This arrangement repeats elements with similar properties after regular intervals. | - |
| Mendeleev's Features | He left blank spaces for elements yet to be discovered, such as germanium, scandium, and gallium. It classified all 63 elements known at the time. | - |
| Groups (Modern Table) | Contains 18 vertical columns. Elements in a group generally have similar electronic configuration in their valence shell and the same number of valence electrons. | - |
| Periods (Modern Table) | Contains 7 horizontal rows. The period number corresponds to the number of shells starting to fill up across the period. | - |
| Periodic Trends (General) | Moving left to right across a Period: Atomic size, Atomic Radius, and Ionic Radius Decrease. Ionization Potential, Electronegativity, and Electron Affinity Increase. | I.A.S. (Pre) 2003 |
| Oxide Nature (Periodicity) | Moving left to right, the nature of oxides changes from alkaline to acidic. | - |
| Electron Affinity Trend | In a group of elements, electron affinity decreases as the atomic weight increases (from top to bottom). | I.A.S. (Pre) 2003 |
| Concept | What to remember | Asked in UPPCS |
|---|---|---|
| Most Abundant Element (Universe) | Hydrogen makes up about 3/4 of all matter, followed by Helium. | UPPCS (Pre) 2007 |
| Most Abundant Element (Earth's Crust) | Oxygen is present in the largest amount (46.60% by mass). | I.A.S. (Pre) 1997 |
| Second Most Abundant Element (Earth's Crust) | Silicon is the second most abundant element (27.72% by mass). Silicon chips are used as a semiconductor in computers. | - |
| Classification of Elements | Elements are generally grouped as Metals, Nonmetals, and Metalloids (or semimetals). | - |
| "Gases" as a Type of Element | Gases are not considered a distinct category of element type (like metal or nonmetal), although specific elements like Helium, Oxygen, etc., are nonmetal elements that exist as gases. | - |
