Chem. (Sem. 1) Flashcards
List examples of a physical change.
grinding, cutting, boiling
List examples of matter.
air, smoke, water vapor
List examples of homogeneous mixtures.
air, sugar in water
What is an example of a pure substance?
vitamin C, water, salt, sugar
A nonmetal usually has what type of property?
brittle, poor conductors
What is the difference between reactants and products?
reactants on the left side of reaction; products on the right side
Example: A +B → AB; A, B are reactants and AB is product
What attracts protons within a nucleus to each other?
nuclear forces
What are ways that Dalton’s atomic theory differs from the modern atomic theory?
- Atoms are divisible into even smaller particles
2. A given element can have atoms with different masses
What is occurring during the law of conservation of mass?
the mass of the products is to equal to the sum of the masses of the reactants
List the five concepts of Dalton’s atomic theory.
- All matter made up of atoms
- Atoms cannot be created or destroyed
- Atoms of an element are alike
- Atoms of different elements differ from one another
- A chemical reaction involves either the union or separation of atoms
How are particles in a nucleus arranged for nuclear forces to exist?
close together
What has to happen in order for an electron in an atom to change from its ground state to excited state?
energy must be absorbed
Define the Aufbau principle.
Electron occupying the lowest available energy orbital
Define Hund’s rule.
Orbitals of equal energy are occupied by one electron before any is occupied by a second electron
What is the most characteristic property of the noble gases?
largely unreactive
