| #3476 |
How does electronegativity vary across a period? |
Increases from left to right |
| #3477 |
What is electronegativity? |
Ability of an atom to attract shared electrons in a covalent bond |
| #3478 |
How does ionization energy vary down a group? |
Decreases down the group |
| #3479 |
How does ionization energy vary across a period? |
Increases from left to right |
| #3480 |
What is ionization energy? |
Energy required to remove the outermost electron from a gaseous atom |
| #3481 |
How does atomic size vary down a group? |
Increases due to addition of electron shells |
| #3482 |
How does atomic size vary across a period? |
Decreases from left to right due to increasing nuclear charge |
| #3483 |
What is atomic size (atomic radius)? |
Distance from the nucleus to the outermost electron of an atom |
| #3484 |
What are groups in the periodic table? |
Vertical columns containing elements with similar chemical properties |
| #3485 |
What are periods in the periodic table? |
Horizontal rows in which properties gradually change |
| #3486 |
What is the modern periodic table based on? |
Increasing atomic number of elements |
| #3487 |
What was Mendeleev’s contribution to chemistry? |
Arranged elements in order of increasing atomic mass and predicted properties of missing elements |
| #3488 |
Who is known as the father of the periodic table? |
Dmitri Mendeleev |
| #3489 |
What is the importance of Avogadro’s number? |
Relates atomic/molecular scale to macroscopic quantities in moles |
| #3490 |
How do isotopes differ in physical properties? |
Different mass affects density, melting point, and radioactivity |
| #3491 |
How do isotopes differ in chemical properties? |
Mostly similar because they have same number of electrons |
| #3492 |
Can atoms form multiple bonds? |
Yes, as in double and triple covalent bonds (O₂, N₂) |
| #3493 |
How does valency affect chemical bonding? |
Determines the number of electrons an atom can gain, lose, or share to form bonds |
| #3494 |
What is the difference between empirical and molecular formula? |
Empirical: simplest ratio of atoms; Molecular: actual number of atoms in a molecule |
| #3495 |
How are chemical equations balanced? |
By ensuring equal number of atoms of each element on both sides of the equation |
| #3496 |
What is the law of conservation of mass in chemical reactions? |
Mass of reactants equals mass of products |
| #3497 |
What is a chemical equation? |
Representation of a chemical reaction using symbols and formulas of elements and compounds |
| #3498 |
What is stoichiometry? |
Calculation of reactants and products in chemical reactions based on balanced equations |
| #3499 |
What is molar mass? |
Mass of 1 mole of a substance in grams |
| #3500 |
What is a mole in chemistry? |
Amount of substance containing 6.022 × 10²³ particles (Avogadro’s number) |