Chemistry XII Unit 2 Questions: 50 Time Limit: 50 minutes Passing Score: 60% Start Quiz Chemistry XII Unit 2 Question 1 of 50 Who discovered electron? J.J. Thomson Rutherford Bohr Millikan What is the charge to mass ratio (e/m) of electron? 1.76 times 10 to power 11 C per kg 1.6 times 10 to power minus 19 C 9.1 times 10 to power minus 31 kg 6.022 times 10 to power 23 What is the charge of electron? 1.6 times 10 to power minus 19 coulombs 1.76 times 10 to power 11 C per kg 9.1 times 10 to power minus 31 kg Zero What is the mass of electron? 9.1 times 10 to power minus 31 kg 1.6 times 10 to power minus 19 C 1.76 times 10 to power 11 C per kg 1.67 times 10 to power minus 27 kg What is Thomson's model of atom called? Nuclear model Plum pudding model Planetary model Quantum model Who proposed nuclear model of atom? Thomson Rutherford Bohr Sommerfeld What is the charge of alpha particle? Plus 2e Minus 2e Plus 1e Zero What is approximate radius of nucleus? 10 to power minus 15 meters 10 to power minus 10 meters 10 to power minus 8 meters 10 to power minus 12 meters What is atomic number (Z)? Number of neutrons Number of protons or electrons Mass number Number of nucleons What is mass number (A)? Number of protons only Number of neutrons only Sum of protons and neutrons Number of electrons What are isotopes? Atoms with same mass number but different atomic number Atoms with same atomic number but different mass number Atoms with different atomic and mass numbers Same atoms What are isobars? Atoms with same atomic number Atoms with same mass number but different atomic number Atoms with same neutrons Same element What are isotones? Atoms with same atomic number Atoms with same mass number Atoms with same number of neutrons Atoms with same electrons What is the formula for number of neutrons? A minus Z Z minus A A plus Z Z divided by A What is wavelength of electromagnetic radiation? Distance between consecutive crests or troughs Speed of light Frequency Energy of photon What is the relation between wavelength and frequency? Lambda equals c divided by nu Lambda equals c times nu Lambda equals nu divided by c Lambda equals c plus nu What is speed of light in vacuum? 3 times 10 to power 8 meters per second 3 times 10 to power 10 cm per second Both are correct Neither is correct What is wavenumber? Number of wavelengths per unit length Wavelength divided by speed Frequency times wavelength Speed divided by frequency What is Planck's constant (h)? 6.626 times 10 to power minus 34 joule second 3 times 10 to power 8 m per s 1.6 times 10 to power minus 19 C 9.1 times 10 to power minus 31 kg What is energy of photon? E equals h times nu E equals h divided by nu E equals nu divided by h E equals h plus nu What is photoelectric effect? Emission of electrons when light falls on metal surface Absorption of light Reflection of light Refraction of light What is work function? Minimum energy required to eject electron from metal surface Maximum energy Average energy Total energy What is threshold frequency? Minimum frequency below which no photoelectric effect occurs Maximum frequency Average frequency Any frequency What is the relation for threshold frequency? Nu zero equals work function divided by h Nu zero equals h times work function Nu zero equals h divided by work function Nu zero equals work function minus h What is kinetic energy of ejected electron? K.E. equals h times nu minus work function K.E. equals work function minus h times nu K.E. equals h times nu plus work function K.E. equals work function What is stopping potential? Potential needed to stop ejected electrons Potential to start photoelectric effect Work function Threshold frequency What is relation between stopping potential and kinetic energy? e times V zero equals K.E. max V zero equals K.E. max e equals K.E. times V zero K.E. equals V zero What is Bohr's first postulate? Electrons revolve in stationary orbits without radiating energy Electrons radiate energy continuously Electrons are stationary Nucleus moves What is Bohr's quantization condition for angular momentum? L equals n times h divided by 2 pi L equals n times h L equals h divided by n L equals 2 pi times n What is the formula for radius of nth orbit? r n equals n squared times 0.53 angstrom r n equals n times 0.53 angstrom r n equals 0.53 divided by n squared r n equals 0.53 times n What is Bohr radius? 0.53 angstrom or 53 pm 1.06 angstrom 0.26 angstrom 1 angstrom What is energy of electron in nth orbit? E n equals minus 13.6 divided by n squared eV E n equals minus 13.6 times n squared eV E n equals plus 13.6 divided by n squared eV E n equals 13.6 eV What is ground state energy of hydrogen atom? Minus 13.6 eV Plus 13.6 eV Zero Minus 27.2 eV What is ionization energy of hydrogen atom? 13.6 eV 27.2 eV 3.4 eV 6.8 eV What is the formula for energy of emitted photon? Delta E equals E i minus E f equals h times nu Delta E equals E f minus E i Delta E equals E i plus E f Delta E equals h divided by nu What is Lyman series? Transitions ending at n equals 1 Transitions ending at n equals 2 Transitions ending at n equals 3 Transitions starting from n equals 1 What is Balmer series? Transitions ending at n equals 1 Transitions ending at n equals 2 Transitions ending at n equals 3 Transitions ending at n equals 4 What is Paschen series? Transitions ending at n equals 2 Transitions ending at n equals 3 Transitions ending at n equals 4 Transitions ending at n equals 5 Which series lies in visible region? Lyman series Balmer series Paschen series Brackett series Which series lies in UV region? Balmer series Paschen series Lyman series Brackett series What is de Broglie wavelength? Lambda equals h divided by m times v Lambda equals m times v divided by h Lambda equals h times m times v Lambda equals m divided by h times v What is Heisenberg's uncertainty principle? Delta x times Delta p greater than or equal to h divided by 4 pi Delta x times Delta p equals zero Delta x equals Delta p Delta x plus Delta p equals h What is principal quantum number (n)? Determines size and energy of orbit Determines shape of orbital Determines orientation Determines spin What is azimuthal quantum number (l)? Determines size of orbital Determines shape of orbital Determines spin Determines magnetic properties What is magnetic quantum number (m)? Determines energy Determines shape Determines orientation of orbital in space Determines spin What is spin quantum number (s)? Determines shape Determines size Determines spin orientation of electron Determines energy What is the maximum number of electrons in an orbit with principal quantum number n? n 2n 2n squared n squared What is Pauli's exclusion principle? No two electrons can have same set of all four quantum numbers All electrons have same energy Electrons pair up first Electrons occupy different orbitals What is Hund's rule? Electrons pair up first Electrons occupy orbitals singly with parallel spins before pairing Electrons have opposite spins All orbitals have same energy What is Aufbau principle? Electrons are added to orbitals in order of increasing energy Electrons occupy highest energy orbitals first All orbitals filled simultaneously Electrons occupy randomly Previous Next Submit Quiz Want to save your progress? Create an account or log in to track your quiz scores! Register/Login