Essential Chemistry Concepts and Atomic Structure Review
Quiz 1 : *
What is the fundamental difference between a homogeneous mixture and a heterogeneous mixture? – A homogeneous mixture has a uniform composition throughout, while a heterogeneous mixture has regions with different compositions. * What is the primary distinguishing factor between an * What is the relationship between milliliters and cubic centimeters? – 1 mL = 1 cm³. * Convert 120,000 miles to kilometers (1 mile=1.609 km)? – 193,080 km *How many gallons are in 5,000 L (1gal = 3.785L)? – 1,321 gal * Which domain of chemistry deals with the study of chemical processes at the
Quiz 2 : *What did Rutherford’s findings suggest about the density of the atomic nucleus compared to the rest of the atom? – The nucleus is incredibly dense compared to the rest of the atom *Which of the following correctly applies Dalton’s Atomic Theory to isotopes of an element? – Isotopes are atoms of the same element with different masses due to varying neutron numbers. *What does the subscript “3” indicate in the chemical formula
NH3? – The compound contains 3 hydrogen atoms *If 10 g of reactant A and 15 g of reactant B produce 20 g of product C, what must occur for the law to hold? – 5 g of another product is formed. *What term is used for isomers that differ in the relative orientation of groups attached to a double bond? – Geometric isomers. *Which unit is Avogadro’s number most commonly associated with? – Per mole. * The mole is defined based on the number of atoms in? – 12 grams of pure carbon-12 (12C). *Which of the following statements best explains why the atomic weight of an element is not an integer? – The atomic weight represents the weighted average of all isotopes of the element. * In a mass spectrum, the height of a peak corresponds to? – The natural abundance of the isotope. *What did the discovery of radioactivity challenge in the context of the prevailing atomic theory of the time? – The theory that atoms were indivisible and unchanging *What did the discovery of the neutron by James Chadwick contribute to atomic theory? – It showed that the nucleus contains both protons and neutrons. *What is the unified atomic mass unit (u) equivalent to in grams? – 1.66054 × 10⁻²⁴ g. *What is the mass number of an isotope of boron with 5 protons and 6 neutrons? – 11 *Which of the following best describes the behavior of cathode rays in Thomson’s experiments? – They were deflected by an electric field, indicating that they are negatively charged. *Which of the following formulas represents the same compound in both molecular and empirical forms? – CH4
Quiz 3 (1): *What does the Bohr radius (α₀) represent in the context of the Bohr model of the atom? – The radius of the first orbit of an electron in a hydrogen atom. * The constant h in Planck’s blackbody radiation law is known as? – Planck’s constant *The uncertainty principle states that when you measure the position of an electron with high precision, what happens to the uncertainty in its velocity? – It increases (you know less about the electron’s velocity). * Why do elements in the same group of the periodic table have similar electron configurations? – They have the same number of valence electrons *Which element has an electron configuration that ends in 4s² 3d⁸? – Nickel (Ni) *What is the frequency of red light with a wavelength of 700 nm in a vacuum? – 4.29×1014 Hz *Which of the following correctly describes the electron configuration of the element sulfur (S)? – [Ne] 3s² 3p⁴ *Which element has the electron configuration [Kr] 5s² 4d¹⁰ 5p¹? – Indium (In). *When using the Rydberg formula to calculate the wavelengths of light emitted by hydrogen, the term n1 is? – The lower energy level to which the electron transitions *Which of the following accurately describes the Pauli Exclusion Principle in the context of electron configuration? – Electrons must have opposite spins when they occupy the same orbital. *Which of the following describes the effect of the 2p orbital’s weaker penetration into the nucleus? – Electrons in the 2p orbital are more shielded from the nucleus than the 2s electrons. *Which equation best describes the relationship in the photoelectric effect? – KE=hν−W0 *For a metal with a work function of 2.3 eV, what happens if light of energy 2.1 eV strikes the surface? – No electrons are emitted. *In the case of a standing wave, what is the effect of increasing the wave’s frequency? – It increases the harmonic number, thus decreasing the wavelength. *Which of the following accurately describes the location of nodes in a standing wave? – Points where the displacement is always zero.
Quiz 3 (2): *What is the empirical formula of a compound with the molecular formula C₆H₁₂O₆? – CH₂O *Which of the following is an example of a molecular (covalent) compound? – CO₂. * What is the formula of the ionic compound formed between aluminum (Al) and chlorine (Cl)?- AlCl₃. * Which of the following would form an ionic compound with the formula Na₂O? – Na and O. *Which of the following elements is most likely to form a +1 ion? – Sodium (Na). *Which of the following factors most strongly influences an atom’s ability to gain or lose electrons? – Effective nuclear charge (Zeff). *Which factor contributes most to the increase in ionization energy as you move across a period from left to right? – Increase in effective nuclear charge (Zeff). *In a covalent bond, the distance between two atoms is determined by? – One-half the distance between the nuclei of two identical atoms. *Which of the following ions will have the smallest ionic radius? – Mg²⁺. * Which ion does not have the same electron configuration as Argon (Ar)? – F⁻. * Which ion has the smallest ionic radius? – Al³⁺. * Which of the following ions would have the largest ionic radius? – I⁻. * What causes the large increase in ionization energy when a noble gas configuration is reached? – The atom achieves a stable electron configuration, making it harder to remove another electron. *The first ionization energies of the elements generally increase as you move from ________ across a period? – Left to right. *What the following will result in the highest first ionization energy? – Noble Gases