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Use proton number and the simple structure of atoms to explain the bases of the periodic table with special reference to the elements of proton number of 1 to 20
Accepted Answer
The periodic table is organized based on the increasing atomic number (number of protons) of elements. Here's how it applies to elements 1-20:
Periods (Rows): Each row represents an energy level (also called an electron shell) where electrons reside. Elements in the same period have the same number of electron shells.
Groups (Columns): Elements within a group share similar chemical properties because they have the same number of valence electrons (electrons in the outermost shell). These electrons participate in bonding.
Example:
Hydrogen (H, atomic number 1): One proton and one electron. It's in Group 1 (alkali metals) and Period 1.
Lithium (Li, atomic number 3): Three protons, three electrons. It's in Group 1 and Period 2.
Carbon (C, atomic number 6): Six protons, six electrons. It's in Group 14 and Period 2.
Trends:
Atomic radius: Generally, atomic radius increases down a group (more electron shells) and decreases across a period (increased nuclear charge pulls electrons closer).
Ionization energy: The energy needed to remove an electron increases across a period (stronger attraction to the nucleus) and decreases down a group (easier to remove electrons from outer shells).
Electronegativity: The ability of an atom to attract electrons increases across a period (stronger nuclear pull) and decreases down a group (weaker attraction).
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