Basic Chemistry

Basic Chemistry

  • Matter and Elements

    • Matter defined as having mass and occupying space

    • Elements are unique forms of matter with specific properties

  • Chemical Bonds

    • Covalent bond involves sharing electrons between atoms

    • Ionic bond involves transferring electrons between atoms

  • Properties of Carbon

    • Key component in biological molecules

    • Can form covalent bonds with up to four different atoms

  • Electrons in Chemical Bonding

    • Atoms interact by sharing or exchanging electrons

    • Electrons play a critical role in chemical bonding

  • Learning Objectives

    • Define matter and elements

    • Explain role of electrons in covalent and ionic bonding

    • Describe properties of carbon

    • Recognize functional groups in biological molecules

  • Terms

    • Include various functional groups and chemical bond types

  • Matter and Elements

    • Life is composed of matter with mass and space

    • Elements are unique forms of matter with specific properties

  • Elements and Atoms

    • Elements cannot be broken down further

    • Each element has a designated chemical symbol

    • Common elements in living organisms: C, O, H, N

  • Elements in Living World

    • Comparison of elements in living organisms and non-living world

    • Percentage composition of elements in life, atmosphere, and Earth's crust

  • Atomic Structure

    • Atom is the smallest unit of matter

    • Contains protons, neutrons, and electrons

    • Nucleus holds protons and neutrons, while electrons orbit around it

  • Sub-atomic Particles

    • Protons, neutrons, and electrons are sub-atomic particles

  • Arrangement in Atom

    • Depiction of sub-atomic particles in an atom (Helium example)

  • Atomic Number and Mass

    • Definition of atomic number and mass

    • Isotopes have different number of neutrons

    • Calculation of neutrons in an element

  • Carbon Isotopes

    • Carbon has atomic number six and stable isotopes with mass numbers twelve and thirteen

  • Isotopes

    • Elements can have different mass numbers due to varying numbers of neutrons

  • Periodic Table

    • Shows atomic mass and number for each element

  • Electron Shells

    • Bohr model explains electron shells and energy levels

    • Electrons fill orbitals in a specific order

  • Valence Shell

    • Most stable configuration when valence shell is filled

    • Group 18 elements have full valence shells

Octet Rule

  • First two outer shells filled with eight electrons

    • Group 1 elements (H, Li, Na) achieve stability by losing an outer electron

    • Group 17 elements achieve stability by gaining an additional electron

Chemical Bonds

  • Force linking atoms to form molecules/compounds

  • Electrons crucial in chemical bonding through sharing/exchanging

  • Atoms interact in reactions to form chemical bonds

Electronegativity

  • Measure of atom's electron attraction in bonds

    • Introduced by Linus Pauling

    • Values on Pauling scale from 0.7 to 4.0

How Do Atoms Bond

  • Atoms bond to form molecules by sharing electrons

  • Example: Two hydrogens and an oxygen form a water molecule

Important Definition

  • Ionic compound formation: metals lose electrons, nonmetals gain for octet

  • Cation: positively charged ion from electron loss

  • Anion: negatively charged ion from electron gain

Polar covalent Bonds

  • Electrons unequally shared, attracted to one nucleus more

  • Example: Water with oxygen having higher electronegativity

Polarity

  • Separation of electric charge in a molecule

  • Example: O and H bond creating a polar bond

Nonpolar Bonds

  • Equal sharing of electrons

  • Example: C-C bond or equal sharing between different elements

Non-Polar Covalent Bonds

  • Electrons equally shared

  • Example: Methane (CH4) with carbon sharing electrons equally

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  • Weaker bonds like Hydrogen bonds between δ+ of hydrogen and δ- of another atom

  • Example: Occurs between water molecules

Carbon

  • Key in macromolecules, forms covalent bonds with up to four atoms

  • Essential for life, unique properties supporting macromolecules

  • Carbon forms covalent bonds with up to four atoms, including other carbons

  • Three types of carbon structures: Straight Chain, Branched Chain, Ring

Functional Group and Macromolecules

  • Functional Groups: atoms in a molecule conferring specific properties

  • Macromolecules have characteristic functional groups interacting via hydrogen bonds