chemisty

Atomic Structure and Elements

• Atoms are composed of subatomic particles: protons (positive charge), neutrons (no charge), and electrons (negative charge).
• Protons and neutrons reside in the nucleus, while electrons orbit the nucleus in electron shells.
• Atomic number defines an element, equivalent to the number of protons.
• Mass number is the total number of protons and neutrons.
• Elements are organized by atomic number and properties on the periodic table.
• Over 100 elements are known.
• Metals are typically found on the left and center of the periodic table; non-metals are on the right, and metalloids exhibit properties of both.

Discovering and Organizing Elements

• Scientists identified elements based on their properties (reactivity, state, atomic weight).
• Mendeleev's periodic table left gaps for undiscovered elements and predicted their properties correctly.
• Elements are arranged based on atomic number (increasing from left to right), chemical properties (similar properties in same groups), and electron configuration.

Properties of Metals and Non-Metals

• Metals form basic oxides whereas non-metals form acidic oxides.
• Metals lose electrons to form positive ions (cations), while non-metals gain electrons to form negative ions (anions).

Compounds and Their Formation

• Compounds have different properties than their constituent elements.
• Compounds are formed through chemical reactions (often irreversible).
• Formation methods include direct combination (element+element reaction), reactions with water, and decomposition reactions(breaking apart a compound into simpler substances).

Naming Compounds

• Binary compounds involve two elements: first element keeps its name and the second is modified to end in -ide.
• Ternary compounds—containing three elements—often include polyatomic ions (with specific names).

Common Types of Compounds

• Oxides (basic from metals, acidic from non-metals)
• Hydroxides (bases, neutralize acids)
• Sulfates (minerals, fertilizers)
• Carbonates (react with acids, produce CO₂)
• Chlorides (salts containing chlorine)

Mixtures and Separation Techniques

• Mixtures (heterogeneous: visible components, homogeneous: uniformly distributed components)
• Separating techniques include filtration, decanting, evaporation, simple distillation, fractional distillation, and chromatography.

Extracting Metals from Ores

• Ores are naturally occurring rocks containing metals.
• Extraction methods include roasting, reduction using carbon, and electrolysis.

Chemical Reactions

• Chemical reactions transform substances into new substances with different properties.
• Signs of a chemical reaction include color change, gas production, temperature change, precipitate formation, and odor change.
• Word equations demonstrate reactants transforming to products (reactants → products).

Corrosion, Identifying Chemicals, and Atomic Structure

• Corrosion is the deterioration of materials due to chemical reactions with the environment (like rust on iron).
• Common gas tests (e.g., hydrogen "pop", oxygen relighting a glowing splint, carbon dioxide turning limewater milky) aid in identifying chemicals.
• Atoms have a nucleus with protons and neutrons, and electrons orbiting in specific energy levels (shells).

Periodic Trends and Isotopes

• Periodic trends such as atomic radius, ionization energy, and reactivity show patterns across the periodic table.
• Isotopes are atoms with the same number of protons but different numbers of neutrons.

Group 1 and 2 Elements, and Halogens

• Group 1 (alkali metals) are highly reactive, reactivity increasing down the group.
• Reactions include alkali + water → metal hydroxide + hydrogen.
• Group 2 (alkaline earth metals) are less reactive than alkali metals.
• Group 7 (halogens) show decreasing reactivity down the group.

More Detail on Subatomic Particles

• Protons and neutrons are composed of quarks and held together by the strong nuclear force.
• Electrons are fundamental particles.
• Electrons arrange themselves in specific shells or energy levels with the first shell holding up to 2 electrons; second up to 8; and third up to 8 (for the first 20 elements).

The Discovery of the Nucleus

• Discovery of the nucleus involved Rutherford's gold foil experiment.

Calculations

• Nucleon number = proton number + neutron number
• Understanding the relationships between protons, electrons, neutrons, and nucleon number is important to understanding atoms and isotopes.

Additional Data

• Chlorination of water involves chlorine reacting with water to produce disinfectants, often hypochlorous acid which is active.

Test your knowledge on atomic structure, subatomic particles, and the organization of elements on the periodic table. This quiz covers essential concepts regarding the mass number, atomic number, and the classification of elements. Perfect for students exploring chemistry fundamentals.