Chapter 4
Describe Dalton's atomic model
The elements are solid spheres that each have a different mass
Explain how the Periodic Table of the elements is organized and structured.
Elements are arranged in order of increasing atomic number. Each row is called a period and each column is called a group. Each row has the same number of energy levels. Each group has the same number of valence electrons, thus making them have similar chemical properties.
Why do atoms exchange or share electrons?
To achieve stable electron configurations. When the highest occupied energy level of an atom is filled with electrons, the atom is stable and not likely to react.
What is a mole?
A mole is an amount of a substance that contains apporximately 6.02 x 10^23 particles of that substance.
What are the 3 ways in which a substance can dissolve in water?
Dissociation of ionic compounds, dispersion of molecular compounds, and ionization of molecular compounds.
Describe the atomic model of Rutherford.
A defined nucleus that held protons with electrons orbiting around it. He did the Gold Foil experiment.
Describe the properties of metals and nonmetals
Metals are elements that are good conductors of electric current and heat. Most are solids at room temperature and are malleable and ductile. Nonmetals are poor conductors of heat and electric current. Many are gasses at room temperature.
How do ionic compounds form?
How do covalent compounds form?
Ionic compounds form when atoms transfer electrons and covalent compounds from when atoms share electrons. A molecule is a neutral group of atoms that are joined together by one or more covalent bonds.
Balance the following chemical formula...
H2 + O2 -> H2O
2H2 + O2 -> 2H2O
What factors affect the rate of dissolving?
Surface area, stirring, and temperature.
Define the components of atom's including their mass, location, and charge.
The nucleus is made up of neutrons (neutral) and protons (positive charge). Electrons (negative charges) are in energy levels that contain orbitals outside the nucleus.
What are valence electrons?
A valence electron is an electron that is in the highest occupied energy level of an atom.
What makes a molecule polar or non-polar?
The type of atoms in a molecule and its shape are factors that determine whether a molecule is polar or nonpolar.
How many moles of oxygen gas were needed if 6 moles of water were produced?
2H2 + O2 -> 2H2O
3 moles of O2 were needed to produce 6 moles of H2O
What factors affect the solubility of a solute?
The polarity of the solvent, temperature, and pressure.
What are isotopes?
Isotopes of an element have the same atomic number but different mass numbers because they have different numbers of neutrons. Example: oxygen - 16 and oxygen-17
What group are the noble gases and what common properties do they share?
Group 8A are the noble gases. Except for Helium, they all have 8 valence electrons which cause them to have low reactivity. They are colorless and odorless.
What is the formula for disphosphorus tetrafluoride?
P2F4 see page 175
What are the 5 general types of reactions?
synthesis, decomposition, single-replacement, double-replacement, and combustion
Describe an acid and a base.
An acid is a compound that produces hydronium ions (H3O+) when dissolved in water. They are usually sour tasting, react with metals, and can change color in indicators. They are also known as proton donors.
A base is a compound that produces hydroxide ions (OH-) when dissolved in water. They are usually bitter tasting, slippery, and can change color in indicators. They are also known as proton acceptors.
What is the mass number?
the sum of the protons and neutrons in the nucleus of that atom
The properties within a period change in a similar way from left to right across the table, except for Period 1. What is the similarity?
Where are the most reactive metals located? What group are the most reactive non-metals located?
Across a period from left to right, the elements become less metallic and more nonmetallic in their properties. The most reactive metals are on the left side of the table. The most reactive nonmetals are on the right in Group 7A(the Halogens).
What is an alloy? What are some examples of alloys?
An alloy is a mixture of two or more elements, at least one of which is a metal. Some examples are bronze (contains copper and tin) and steel (iron with carbon)
What factors affect reaction rates?
What factors cause a shift in equillibrium?
Factors that affect reaction rates include temperature, surface area, stirring, concentration, and catalysts.
Factors that cause a shift in equilibrium are temperature, pressure, and concentration.
Low pH values have a greater concentration of what ion?
H3O+