IndietroIntroduction to Chemistry - Key Concepts
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Termini in questo insieme (20)
Matter is neither created nor destroyed in a chemical reaction; total mass of reactants equals total mass of products.
Different samples of a pure compound always contain the same proportion of elements by mass.
Elements combine in different ways to form different compounds, with mass ratios that are small whole-number multiples of each other.
Atoms are tiny, indestructible particles; atoms of the same element have the same mass; atoms combine in whole-number ratios; chemical reactions rearrange atoms.
J.J. Thomson discovered the electron as a tiny, negatively charged particle using cathode-ray tube experiments.
Determined the charge and mass of the electron by observing charged oil drops in an electric field.
Model where electrons are embedded in a uniform positive charge 'soup' within the atom.
Radiation consists of alpha particles (helium nuclei) and beta particles (high-energy electrons).
Showed that atoms are mostly empty space with a small, dense, positively charged nucleus.
The number of protons in the nucleus; equals the number of electrons in a neutral atom.
The sum of the number of protons and neutrons in the nucleus.
Atoms with the same atomic number but different mass numbers due to varying neutrons.
Atoms that have gained or lost electrons, becoming charged particles: cations (+) and anions (−).
Defined as 1/12 the mass of a carbon-12 atom; also called Dalton (Da).
The weighted average of the isotopic masses of an element's naturally occurring isotopes.
The percentage of each isotope present in a naturally occurring sample of an element.
SI unit for amount of substance; 1 mol = 6.022 × 10\(23\) particles.
The mass in grams of 1 mole of an element; numerically equal to the atomic mass in amu.
Use molar mass as a conversion factor: \(\text{mass (g)} \leftrightarrow \text{moles}\).
Use Avogadro's number as a conversion factor: \(\text{moles} \leftrightarrow \text{number of particles}\).