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
What is a positive ion known as? Negative ion?
positive-cation negative-anion
What is removed when the ionization energy is supplied to an atom of an element?
electron
What is the maximum number of electrons in the s sublevel? p-sublevel? d-sublevel? f-sublevel?
s-2 p-6 d-10 f-14
Review the rules for the trends in atomic radius, ionization energy, and electronegativity in elements across a period and down a group.
Atomic radius-decrease across period; increase down group
Ionization energy- increase across period; decrease down group
Electronegativity- increase across period; decrease down group
Valence electrons are found in the s and p blocks and in which energy level?
highest energy level
How many electrons are in the Lewis structure for a hydroxide ion, OH-.
8 O-6 H-1 + 1= 8
What are shared in a covalent bond?
electrons
Electrons involved in a chemical bond are called what?
valence electrons
If atoms that share electrons have an unequal attraction for the electrons, what type of bond does this result in?
polar covalent
As independent particles, most atoms have what kind of energy?
high potential energy
Compared with ionic compounds, molecular compounds have what?
lower melting points
To appear shiny, a material must be able to do what?
absorb and re-emit light of many wavelengths
The properties of both ionic and molecular compounds are related to what?
strengths of attraction between the particles in the compounds
Define malleability.
a material that can be shaped, such as hammering
What does the chemical formula for an ionic compound represent?
ratio of the combined ions present in a sample
Within a compound, be able to identify which atom would have a partial positive charge and partial negative charge.
HCl H= positive charge Cl= negative charge
