Matter, Chemical Bonding, Etc Flashcards
What is chemistry?
The study of matter and its changes and properties
What is matter?
Anything that has mass and takes up space
What are the two types of matter and the two groups within each?
Mixtures: heterogeneous/mechanical mixtures and homogeneous/solutions
Pure substances: elements and compounds
Explain heterogeneous mixtures
2 or more components with two or more visible phases. Variable composition. Can be separated by physical means. (Ex. Pizza)
Also: suspensions (ketchup, paint) and Colloids (particles can’t be seen with naked eye, milk)
Explain homogeneous mixtures.
Two or more components. Only see one phase. Variable composition. Can be separated by physical means. Ex. Salt water, air, alloids
Explain elements
Simplest pure substance. Can’t be decomposed. Found in periodic table. Represented with symbols.
Explain compounds
Two or more elements. Constant composition. Decomposed by chemical means. Represented by formulas. Smallest particles are molecules.
Give examples of physical properties.
The appearance: texture, colour, state, clarity, hardness, melting point, boiling point
Five proofs of chemical change
- Gas is released (fizzing, bubbling, foaming)
- Energy is released or absorbed
- Precipitate formation
- True colour change
- Hard to reverse
What did Democritus propose?
First atomic theory. If matter is divided into smaller and smaller pieces, there will eventually be a part that can no longer be divided (the atom)
What did john dalton contribute to the atomic theory?
Billiard ball model. All ,after consists of particles called atoms. Atoms of each element are unique. Atoms are undivisible.
What did JJ Thompson contribute?
Cathode ray tubes. Raisin bun model.
Rutherford’ contribution
Gold foil. Conclusion: matter consists of mostly empty space with a positive nucleus
Explain how to find protons, neutrons, electrons
Atomic number = e and p
N = mass number -protons
List the maximum number of electrons in each level (s, p, d, f)
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14
What letter describes each thing: energy level, shape, orientation, spin)
Energy level is n
Shape is l
Orientation is m
Spin is S
What is an isotope?
Atoms of an element that contain the same number of protons but different number of neutrons. Therefore have different masses.
Describe unstable isotopes
Have excess nuclear energy. Radioactive. Emit radiation. Called radioisotopes.