GS One‑Liners

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# Question & Answer
4026
How does electronegativity vary across a period? - Increases from left to right
4027
What is electronegativity? - Ability of an atom to attract shared electrons in a covalent bond
4028
How does ionization energy vary down a group? - Decreases down the group
4029
How does ionization energy vary across a period? - Increases from left to right
4030
What is ionization energy? - Energy required to remove the outermost electron from a gaseous atom
4031
How does atomic size vary down a group? - Increases due to addition of electron shells
4032
How does atomic size vary across a period? - Decreases from left to right due to increasing nuclear charge
4033
What is atomic size (atomic radius)? - Distance from the nucleus to the outermost electron of an atom
4034
What are groups in the periodic table? - Vertical columns containing elements with similar chemical properties
4035
What are periods in the periodic table? - Horizontal rows in which properties gradually change
4036
What is the modern periodic table based on? - Increasing atomic number of elements
4037
What was Mendeleev’s contribution to chemistry? - Arranged elements in order of increasing atomic mass and predicted properties of missing elements
4038
Who is known as the father of the periodic table? - Dmitri Mendeleev
4039
What is the importance of Avogadro’s number? - Relates atomic/molecular scale to macroscopic quantities in moles
4040
How do isotopes differ in physical properties? - Different mass affects density, melting point, and radioactivity
4041
How do isotopes differ in chemical properties? - Mostly similar because they have same number of electrons
4042
Can atoms form multiple bonds? - Yes, as in double and triple covalent bonds (O₂, N₂)
4043
How does valency affect chemical bonding? - Determines the number of electrons an atom can gain, lose, or share to form bonds
4044
What is the difference between empirical and molecular formula? - Empirical: simplest ratio of atoms; Molecular: actual number of atoms in a molecule
4045
How are chemical equations balanced? - By ensuring equal number of atoms of each element on both sides of the equation
4046
What is the law of conservation of mass in chemical reactions? - Mass of reactants equals mass of products
4047
What is a chemical equation? - Representation of a chemical reaction using symbols and formulas of elements and compounds
4048
What is stoichiometry? - Calculation of reactants and products in chemical reactions based on balanced equations
4049
What is molar mass? - Mass of 1 mole of a substance in grams
4050
What is a mole in chemistry? - Amount of substance containing 6.022 × 10²³ particles (Avogadro’s number)