Semmelweis Entrance Exam (N) 2024/2025 Questions with Complete Solutions The mole concept - Correct Answer A method that allows the relative number of reactant particles involved in a chemical reaction to be known Avogadro's number - Correct Answer number of representative particles in a mole, 6.02 X 10^23 Basic structures of atoms - Correct Answer There is a nucleus in the center surrounded by an electron cloud or field Quantum numbers - Correct Answer Quantum numbers describe values of conserved quantities in the dynamics of a quantum system. In the case of electrons, the quantum numbers can be defined as "the sets of numerical values which give acceptable solutions to the Schrödinger wave equation for the hydrogen atom" Common compounds - Correct Answer Water (H2O), table salt (NaCL); carbon dioxide (CO2); baking soda (NaHCO3); carbon monoxide (CO); sand or glass (SiO2) Periodic properties - Correct Answer chemical or physical properties that vary among elements according to trends that repeat as atomic number increases What are the periodic properties? - Correct Answer Element (on periodic table) - Correct Answer Atomic number is the same as - Correct Answer number of protons Atomic mass is the same as - Correct Answer Number of protons and neutrons Different types of chemical bonding - Correct Answer metallic, covalent, ionic 1 / 2
What is covalent bonding and how does it work? - Correct Answer when atoms share one or more pairs of electrons. They have similar electronegativities What is ionic bonding? - Correct Answer when atoms transfer electrons. Large difference in electronegativity Examples of ionic bonds - Correct Answer NaCl Cs2O MgO
NH4NO3
Examples of covalent bonds - Correct Answer F2, O2, N2, H2, CL2, HCL, H2O What is metallic bonding? - Correct Answer the chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons What is hydrogen bonding? - Correct Answer Hydrogen bonding is the strongest intermolecular force. it only happens when hydrogen is covalently bonded to fluorine, nitrogen or oxygen because they're very electronegative and can pull the bonding electrons away from the hydrogen.Substances with hydrogen bonding have higher melting and boiling points because of the extra energy needed to break the hydrogen bonds.What is a dipole-dipole force? - Correct Answer The attraction between the positive end of one polar molecule and the negative end of another What is a london dispersion force? - Correct Answer weak forces that result from temporary shifts in the density of electrons in electron clouds What is the lewis structure? - Correct Answer diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.
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