| #3501 |
What is a metallic bond? |
Bonding in metals where electrons are delocalized and shared collectively in a lattice |
| #3502 |
Give an example of a covalent compound. |
Water (H₂O), Methane (CH₄) |
| #3503 |
What is a covalent bond? |
Bond formed by sharing of electrons between two atoms |
| #3504 |
Give an example of an ionic compound. |
Sodium chloride (NaCl) |
| #3505 |
What is an ionic bond? |
Bond formed by transfer of electrons from one atom to another, resulting in cations and anions |
| #3506 |
What is the octet rule? |
Atoms tend to gain, lose, or share electrons to have eight electrons in their valence shell |
| #3507 |
What is valency? |
Combining capacity of an atom, usually equal to the number of electrons gained, lost, or shared |
| #3508 |
What are isobars? |
Atoms of different elements with the same mass number but different atomic numbers |
| #3509 |
What are isotopes? |
Atoms of the same element with same number of protons but different number of neutrons |
| #3510 |
What is the relative charge and mass of a neutron? |
Charge = 0, Mass ≈ 1.67 × 10⁻²⁷ kg |
| #3511 |
What is the relative charge and mass of a proton? |
Charge = +1 e, Mass ≈ 1.67 × 10⁻²⁷ kg |
| #3512 |
What is the relative charge and mass of an electron? |
Charge = -1 e, Mass ≈ 9.11 × 10⁻³¹ kg |
| #3513 |
What are the three subatomic particles? |
Electrons (negative), Protons (positive), Neutrons (neutral) |
| #3514 |
What is Bohr’s contribution to atomic structure? |
Electrons revolve in fixed orbits with quantized energy levels |
| #3515 |
Who proposed the Bohr model of the atom? |
Niels Bohr |
| #3516 |
What was Rutherford’s model of the atom? |
Atom has a small, dense positively charged nucleus with electrons orbiting around it |
| #3517 |
Who discovered the nucleus of an atom? |
Ernest Rutherford |
| #3518 |
What was Dalton’s contribution to atomic theory? |
Atoms are indivisible, indestructible, and identical for a given element |
| #3519 |
Who proposed the first atomic theory? |
John Dalton |
| #3520 |
How does a step-up transformer differ from a step-down transformer? |
Step-up: increases voltage, decreases current; Step-down: decreases voltage, increases current |
| #3521 |
What is a solenoid used for? |
Creating controlled magnetic fields and as electromagnets |
| #3522 |
Can Ohm’s law be applied to all conductors? |
No, only for ohmic conductors where resistance remains constant |
| #3523 |
What is the difference between series and parallel circuits? |
Series: same current, voltage divides; Parallel: same voltage, current divides |
| #3524 |
How does resistance heating work? |
Electric current through a high-resistance material produces heat (I²R) |
| #3525 |
What is the role of electromagnets in practical applications? |
Used in motors, relays, cranes, and MRI machines |