General, Organic, and Biological Chemistry: Atoms and Elements

  • Identifying an element as a metal, a non-metal or a metalloid

  • Properties/characteristics of metals and non-metals

  • Groups of elements (for example, you need to know which element is a transition metal, an alkali metal, a noble gas etc.)

  • Also, keep in mind, elements within the same group have similar chemical and physical properties

  • Subatomic particles (including their masses, charges and locations)

  • Should be able to determine the number of protons, electrons, neutrons, atomic number, mass number for any of the elements

  • Isotopes, identifying atoms which are isotopes

  • Identifying the most abundant isotope

  • Energy levels, maximum number of electrons in each level

  • Electron configuration

  • Periodic trends including ionization energy, atomic radius, metallic/non-metallic character (identifying an element with the lowest/highest ionization energy, metallic/non-metallic characteristics, atomic radius)

  • Subnuclear particles (including alpha particles, beta particles, positrons, gamma radiation)

  • Nuclear equations including an alpha decay, beta decay, positron emission, identifying an isotope produced or a particle released

  • Half-life problems

  • Fission and fusion nuclear reactions

General Concepts of Chemistry

Elements

  • Definition: Elements are pure substances from which all other things are built.

  • **Characteristics:

    • Cannot be broken down into simpler substances

    • Listed in the periodic table on the front cover of the text.

Chemical Symbols

  • Represent the names of the elements.

  • Format: One or two letters; starts with a capital letter.

One-Letter Symbols

  • C - carbon

  • N - nitrogen

  • O - oxygen

  • H - hydrogen

  • F - fluorine

  • P - phosphorus

  • S - sulfur

Two-Letter Symbols

  • Ca - calcium

  • Co - cobalt

  • Al - aluminum

  • Ar - argon

  • Au - gold (from Latin: aurum)

  • Hg - mercury (from Latin: hydrargyrum)

  • Fe - iron (from Latin: ferrum)

  • Ag - silver (from Latin: argentum)

Periodic Table

  • Definition: A table organizing 118 elements into groups with similar properties and in order of increasing atomic mass.

  • Elements arranged by:

    • Groups (Vertical Columns): Elements with similar properties.

    • Periods (Horizontal Rows): Numbered from top to bottom (1-7).

Group Names

  1. 1A (Alkali Metals): Li, Na, K, Rb, Cs

  2. 2A (Alkaline Earth Metals): Be, Mg, Ca, Sr, Ba, Ra

  3. Transition Elements: Groups 3B-2B

  4. 7A (Halogens): F, Cl, Br, I

  5. 8A (Noble Gases): Typically unreactive gases.

Properties of Metals, Nonmetals, and Metalloids

  • Metals:

    • Found on the left side of the periodic table.

    • Shiny, ductile, conduct heat and electricity, solid (except Hg).

  • Nonmetals:

    • Found on the right side.

    • Dull, brittle, poor conductors, low density and melting points.

  • Metalloids:

    • Found along the zigzag line.

    • Exhibit properties of both metals and nonmetals, used as semiconductors/insulators.

Chemical Properties of Elements

Ionization Energy and Atomic Size

  • Ionization Energy: Energy required to remove an outermost electron.

    • Decreases down a group; increases across a period.

  • Atomic Size:

    • Increases down a group; decreases across a period.

Subatomic Particles

  • Definition: Atoms are composed of smaller particles: protons, neutrons, and electrons.

    • Protons: Positive charge, located in the nucleus.

    • Neutrons: Neutral charge, also in the nucleus.

    • Electrons: Negative charge, occupy space around the nucleus.

Electrical Charges in an Atom

  • Like charges repel; unlike charges attract.

Atomic Number and Mass Number

  • Atomic Number:

    • Specific whole number for each element; equals the number of protons.

    • Example: H = 1 proton, C = 6 protons.

  • EleMass Number:

    • Total number of protons and neutrons in an atom's nucleus.

    • Not listed on the periodic table; varies for isotopes of an element.

Isotopes

  • Definition: Atoms of the same element with different mass numbers.

  • Same number of protons, but different number of neutrons.

ctron Configuration

  • Arrangement of electrons in an atom influences its properties.

  • Energy Levels and Sublevels: Electrons occupy various levels (n=1, 2, 3…) and sublevels (s, p, d, f).

    • Pauli Exclusion Principle: An orbital can hold a maximum of two electrons with opposite spins.

Trends in the Periodic Table

a. Valence Electrons:

  • Chemical properties of representative elements tied to external electrons.

  • The group number indicates the number of valence electrons.

b. Metallic Character:

  • Increases down a group; decreases across a period.

  • Metals lose electrons easily, nonmetals do not.

Connecting Chemistry to Health

  • 20 elements are essential for human survival; 4 elements (H, C, O, N) compose 96% body mass.

  • Macrominerals (Ca, P, K, Cl, S, Na, Mg) crucial for various physiological functions (muscle contraction, nerve impulses, etc.).

Learning Checks

  1. Identify element in Group 7A (17), Period 4: Br

  2. Identify alkaline earth metal: Mg

  3. Element similar to S: O

  4. Characteristics of Metals, Nonmetals, Metalloids appropriate.

  5. Identify isotopes and calculate based on the provided atomic numbers.