GENERAL CHEMISTRY 2024-2025 Past Paper PDF

‫جامعة العين‬ ‫الكلية التقنية الصحية والطبية‬ ‫المرحلة االولى‬- ‫قسم تقنيات االشعة والسونار‬ Review Of Atom, Molecular Structure, Electronic Distribution, Chemical Bonding GENERAL CHEMISTRY 2024-2025 Dr. Ahmed jaber Lec(1)...

‫جامعة العين‬ ‫الكلية التقنية الصحية والطبية‬ ‫المرحلة االولى‬- ‫قسم تقنيات االشعة والسونار‬ Review Of Atom, Molecular Structure, Electronic Distribution, Chemical Bonding GENERAL CHEMISTRY 2024-2025 Dr. Ahmed jaber Lec(1) Dr. ahmed jaber Review of Atom  Atoms are the extremely small particles that are the basic building blocks of ordinary matter.  The atomic structure of an element refers to the constitution of its nucleus and the arrangement of the electrons around it. Primarily, the atomic structure of matter is made up of protons, electrons and neutrons. Dr. ahmed jaber Atoms consist of an extremely small, positively charged nucleus surrounded by a cloud of negatively charged electrons. Although typically the nucleus is less than one ten-thousandth the size of the atom, the nucleus contains more that 99.9% of the mass of the atom. Nuclei are made of positively charged protons and electrically neutral neutrons held together by a nuclear force. This force is much stronger than the electrostatic force that binds electrons to the nucleus, but its range is limited to distances of the order of 1 x 10-15 meters. Dr. ahmed jaber  There are three subatomic particles: protons, neutrons and electrons. Two of the subatomic particles have electrical charges: protons have a positive charge while electrons have a negative charge. the properties of subatomic particles Dr. ahmed jaber Review of Atomic Terms Nucleons – particles found in the nucleus of an atom neutrons and protons Atomic Number (Z) – number of protons in the nucleus Mass Number (A) – sum of the number of protons and neutrons Isotopes – atoms with identical atomic numbers but different mass numbers Nuclide – each unique atom Dr. ahmed jaber Atomic Models 1-Dalton’s Atomic Theory: Proposed that atoms are indivisible and indestructible, forming the building blocks of matter. 2-Thomson’s Plum Pudding Model: Suggested that electrons are embedded in a positively charged sphere. 3-Rutherford’s Model: Demonstrated that atoms have a dense, positively charged nucleus surrounded by electrons. Dr. ahmed jaber 4-Bohr’s Model: Introduced the idea of quantized energy levels where electrons reside. 5-Quantum Mechanical Model: The most advanced model describes electrons as existing in orbitals—regions of space where there is a high probability of finding an electron. Dr. ahmed jaber Molecular Structure  Molecules form when atoms combine through chemical bonds. The arrangement of atoms in a molecule determines its structure and properties. Types of Molecular Structures 1-Linear: Atoms arranged in a straight line (e.g., CO₂). 2-Trigonal Planar: Atoms form a triangle on a single plane (e.g., BF₃). Dr. ahmed jaber 3- Tetrahedral: Four atoms form a pyramid around a central atom (e.g., CH₄). 4-Bent or Angular: Atoms form an angular shape (e.g., H₂O). Dr. ahmed jaber 5- Trigonal Bipyramidal and Octahedral: Found in larger, more complex molecules (e.g., PCl₅, SF₆). Trigonal Bipyramidal Octahedral PCl5 SF6 Dr. ahmed jaber Electrons Distributed in Different Orbits (Shells)  The distribution of the electrons in the energy shells is known as electronic configuration. It is based on Bohr-Bury scheme according to which The maximum number of electrons that can be present in a particular energy shell of an atom is given by Maximum electrons per shell = 2𝒏𝟐 Where n is the number of energy shell The order of energy of these energy shells starting form nucleus is K