Chemistry II & III: Periodic Table - Study Guide

Group 17: Halogens

The elements in this group of the periodic table react with metals to form salts. Because they react quickly with other elements, they occur naturally only as compounds. Elements include: The gases Fluorine (F) and Chlorine (Cl), the liquid Bromine (Br), and the solids Iodine (I) and Astatine (At) They are generally less reactive as you move down the group in the periodic table.

Group 18: Noble Gases

The elements in this group of the periodic table react with other elements only under special conditions. Element include: The gases Helium (He) (exception), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn). Each of these gases have eight valence electrons and are stable. They were not yet discovered when Dimitri Mendeleev constructed his periodic table.

Two

The maximum number of electrons in the first energy level of the atom that is closest to the nucleus.

Eight

The maximum number of electrons in the second energy of the atom. Many atoms are stable with this amount of electrons are stable.

Atomic Number

The number of protons in the nucleus of an atom of an element. Increases as you read left to right across each period.

Happens in a molecule of water

The oxygen atom attracts the electrons more strongly than each hydrogen atom does.. Because the electrons have a slight negative charge, there is a slight negative charge near the oxygen atom; there is a slight positive charge near the hydrogen atoms.

Elements in Groups 13-16

The solids Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po), and (At).

produced, properties

The starting substances and the substances ________ have different physical and chemical __________.

Lanthanide Series

The top row of the transition elements at the bottom of the periodic table.

How to figure out the charge of an ion

To figure it out, subtract the number of electrons in the ion from the number of protons

All elements in the same group have similar properties

What is true about elements in the same group?

They change in chemical and physical properties

What is true about the characteristics of elements in a period from left to right on the periodic table?

The amount of protons/increasing atomic number

What is used to create sequential order of elements?

nonmetal

When a metal and a(n) ________ bond, they don't share electrons. The metal atom transfers one or more valence electrons to the nonmetal atom, forming a chemically stable compound.

gain, lost

When forming a chemical compounds, the nonmetal atoms ____ the electrons ____ by the metal atoms. Due to the change in the number of electrons, the metal and nonmetal atoms both become ions.

placement

You can identify the properties of an element by studying its _________ on the periodic table.

Triple Covalent Bond

A bond where 3 pairs of valence electrons are shared between two atoms. Is stronger than a double covalent bond.

Periodic Table

A chart of the elements arranged according to their physical and chemical properties. It can be used to determine how all elements are related to one another. Each block on the chart describes basic properties of one element.

Covalent Bond

A chemical bond formed when two or more atoms of different nonmetals share one or more pairs of valence electrons and molecules (nonmetals). Valence electrons are shared between oxygen and hydrogen atoms, thereby forming this bond to make three stable atoms. One atom can attract the shared electrons more strongly than the other atom can in this bond. They are made up of many molecules. They are usually gases or liquids at room temperature and have low melting and boiling points. They are also poor conductors of electricity in any form. Atoms share one or more electrons with each other to form the bond. Each atom is left with a complete outer shell.

Endothermic Reaction

A chemical reaction in which thermal energy is absorbed. Examples: Frying an egg, freezing, and fire giving off heat. *Transfer energy to the environment (surroundings get hotter.)*

Stable Atoms and Unstable Atoms

Atoms that don't react easily with or form bonds with other atoms. These atoms have 4 pairs of valence electrons. Atoms with at least one unpaired electron and can become stable only by forming chemical bonds with other atoms.

Chemical Change

Change where new substances form.

Compounds

Chemical combinations of two or more elements. These and the elements that form them frequently have different chemical and physical properties. Most of the matter around is made up of these. Atoms can bond to form these by sharing valence electrons.

similar

Elements near each other on the periodic table share _______ properties.

Metallic Bond

Formed when many metal atoms share their pooled valence electrons.

Double Covalent Bond

Is formed when inside a carbon dioxide molecule, and the carbon atoms shares 2 pairs of valence electrons with each oxygen atom. Is stronger than a single covalent bond.

Single Covalent Bond

Is formed when inside a hydrogen molecule, and when each hydrogen atom shares its valence electrons with the other.

Synthetic Elements

Latest elements added to the periodic table and are man-made.

metal atoms

Metal atoms form compounds with other _____ _____ by combining, or pooling, their valence electrons. When metals atoms lose their valence electrons, they become positive ions. Valence electrons in metals aren't bonded to any particular atom; instead, positive metal ions are surrounded by a sea of electrons.

one, lose

Sodium is a metal that has ___ valence electron. To become stable, it has to ____ a valence electron. When a sodium atom loses a valence electron, it becomes a(n) positively charged ion.

Law of Conservation of Mass

States that the total mass of the reactants before a chemical reaction is the same as the total mass of the products after the chemical reaction. Mass is conserved in a chemical reaction because atoms are conserved. To show that mass is conserved, a chemical equation must show that the number of each type of atom must be balanced, or the same on both sides of the equation.

Malleability

The ability of a substance to be bent, hammered or rolled into thin sheets without breaking or shattering.

Brittle

The ability of a substance to break easily.

Energy Level

The amount of energy an electron can have.

Elements in Groups 14-16

The gas Nitrogen (N) and the solid Phosphorus (P). *The solid Carbon (C) is in group 14* The gas Oxygen (O) and the solids Sulfur (S) and Selenium (Se).

Valence Electrons

The outermost electrons in an atom that participate in chemical bonding. The outermost electrons are less strongly attached to the nucleus. Number of these in an atom tells you how many bonds the atom can form. Each element in the same group in the periodic table has the same number of these. Atoms tend to gain, lose, or share these until each atom has the same number of these as the Noble Gases.

Exothermic Reaction

A chemical reaction in which thermal energy is released. Examples: Fireworks exploding, burning a log in the fireplace, and photosynthesis, such as a melting snowman. *Take in energy from the surroundings (surroundings get colder).*

atoms, substances

A chemical reaction is a process in which _____ of one or more __________ rearrange to form one or more new substances.

Group/Family

A column on the periodic table.

Chemical Equation

A description of a reaction using element symbols and chemical formulas. Is balanced by adding coefficients.

Copper (Cu)

A good conductor of thermal energy and electricity that is commonly used in cookware.

Molecule, covalent compounds

A group of atoms held together by covalent bonding that acts as an independent unit. ________ _________ generally have low melting points and low boiling points and are poor conductors of electricity.

Subscript

A letter or number immediately below to the right or left of another character.

Polar Molecule

A molecule that has a slight positive end and a slight negative end because of unequal sharing of electrons. Examples such as sugar and water dissolve easily in one another because of the attraction of opposite charges.

Chlorine

A nonmetal that has seven valence electrons. To become stable, the element has to gain a valence electron. When an atom of this gains a valence electron, it becomes a(n) negatively charged ion.

Coefficient

A number placed in front of an element symbol or a chemical formula in an equation used to multiply a variable.

Period

A row on the periodic table.

Four

Amount of elements most of the mass of your body is composed of.

Anion

An atom that gains one or more valence electrons.

Ion

An atom that is no longer electrically neutral because it has gained or lost one or more valence electrons.

Cation

An atom that loses or more valence electrons.

unstable

An atom with at least one unpaired electron is ________.

Nonmetal

An element that has no metallic properties.

periodic table, properties

An element's position on the ________ _____ tells a lot about the element. Understanding the __________ of elements can help you decide which element to use in a particular situation.

increase, increase

As you go from right to left across the periodic table, metallic properties of elements tend to ________. As you go from the top of a group of elements to the bottom of the group, the metallic properties of the group tend to ________.

increases

As you read from left to right across the periodic table, the atomic number _________ by one for each element.

Hydrogen (H)

Atomic number: 1 - It is a non-metal. - It is a gas. - It is in period 1, group 1.

Iron (Fe)

Atomic number: 26 - It is a metal. - It is a solid. - It is in period 4, group 8.

Cobalt (Co)

Atomic number: 27 - It is a metal. - It is a solid. - It is in period 4, group 9.

Arsenic (As)

Atomic number: 33 - It is a metalloid. - It is a solid. - It is in period 4, group 15.

Carbon (C)

Atomic number: 6 - It is a non-metal. - It is a solid. - It is in period 2, group 14. - It is the only non-metal in group 14 of the periodic table. - Most of the compounds that make up organisms contain this.

Platinum (Pt)

Atomic number: 78 - It is a metal. - It is a solid. - It is in period 6, group 10.

Covalent Bonds

CO2 NH4CL H2O HCI NO2 CH4 SO3 P205 N203

Ionic Bonds

CaCl2 MgO BaSO4 KI K20 NaOH NaF Na2CO3 AIPO4 FeCl3 LiBr

Physical Change

Change where no substances are produced.

Luster

Describes the ability of a metal to reflect light.

Henry Moseley

Early 1900's: Found that the problem with Mendeleev's table could be solved if the elements were arranged in rows by atomic number.

least, most

Electrons closest to the nucleus have the _______ energy; electrons farthest from the nucleus have the ______ energy.

elements

Element symbols represent ________. When an element exists as a(n) diatomic molecule, the element symbol is followed by the subscript 2.

Alkali Metals

Elements in group 1 of the periodic table. The elements in this group include: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr). Because they react quickly with other elements, they exist in nature only as compounds and are very reactive as oxygen. Pure substances of this are silver in color, soft, and have low densities.

Alkaline Earth Metals

Elements in group 2 of the periodic table. The elements in this group include: Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium. They react quickly, but they are not quite as reactive as alkali metals and alkaline earth metals, but still occur naturally only as compounds and not freely. They are silver in color and soft, have a low density, but have a greater density than alkali metals.

Transition Elements

Elements in groups 3 - 12 of the periodic table. Examples: Cobalt (Co), Silver (Ag), Zinc (Zn). They are shown in two blocks in the periodic table; one block is in the center and the other block includes two rows at the bottom of the table. They have higher densities, greater strength, higher melting points, and are less reactive than alkali metals and alkaline earth metals with oxygen and water. Some can exist in nature as free elements. They are used for building materials, coins/jewelry, electrical wires, industrial applications, paints, and pigments. The color in gems, such as emeralds, come from their presence.

chemical properties

Elements in the same group have similar ________ __________, which means they react with other elements in similar ways.

Metals on the Periodic Table

Elements left and middle of the "stair step" or "zig zag line" (with the exception of Hydrogen) on the periodic table. They make up more than 70% of all elements on the Periodic Table and are mostly solids at room temperature. They are also typically silver or gray in color and are shiny in appearance, such as Mercury, but it is the only one that is actually a liquid at room temperature.

Metals

Elements that are generally shiny because the valence electrons at their surface interact with light, are easily pulled into thin sheets, and are good conductors of electricity and thermal energy. They have high melting points + boiling points and are good conductors of heat and electricity because their valence electrons can easily move from ion to ion, transferring electric charge and are malleable because the ions slide past one another through the electron pool.. They are also ductile. Most are solid or solid crystals at room temperature have no luster. Are poor conductors and are good insulators.

Metalloids

Elements that border the "stair step" or "zigzag line" (with the exception of aluminum). The 8 of include are Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po), and Astatine (At). They have characteristics of both physical and chemical properties of metals and nonmetals, and are a little more difficult to describe. A key property is that they are generally semiconductors, such as Silicon, which is used in computer chips and circuits boards for this reason. The main elements used in microchips are pure Silicon (Si) and Germanium (Ge).

Nonmetals

Elements to the right of the "stair step" are "zig zag line". They have the exact opposite properties of metals. They aren't typically silver or gray and are dull in appearance. The majority of them are gases at room temperature. They have low melting pointing and are poor conductors of heat and electricity. Solid examples are brittle and have no luster.

solid

Except for merucry, all metals are _______ at room temperature.

Chemical Formula

Group of chemicals symbols and numbers that represent the elements and the numbers of atoms of each element in a compound. The letters in this represent elements.

group

Metals in the same _____ in the periodic table usually have very similar chemical properties.

Dimitri Mendeleev

Mid 1800's: Russian chemist and teacher created a table to help classify the elements by their properties. Placed the elements in rows of increasing atomic mass. Elements in the table showed repeating patterns; PERIODIC is used to describe such patterns. For example, he noticed patterns in the melting point of elements and after arranging the known elements in a periodic table, he noticed large gaps between some elements. He predicted that scientists would find new elements to fill these spaces. His predictions were correct.

Electron Dot Diagram

Model that represents valence electrons in an atom as dots around the element's chemical symbol. To create the model, draw one dot for each electron in the atom, placing one dot on each of the four sides of the symbol and then pairing additional dots. The number of unpaired dots in the model tells you how many bonds an atom can form.

Ionic Compounds

Most are solid or solid crystals and brittle at room temperature. They also usually have high melting points and boiling points. They dissolve easily in water. Are composed of a large collection of ions, all of which attract each other and are held together by ionic bonds.

Hydrogen

Only nonmetal not located on the left side of the periodic table. It is the most common element in the universe. It is like a non-metal because it is a gas at room temperature. The liquid form of this is like a semiconductor because it conducts electricity well.

Main-Block Transition Elements

React with other elements and form colorful compounds, some of which are used in paints and pigments.

Lewis Structure Model

Represents valence electrons of atoms in a molecule.

properties

Scientists use the periodic table to predict the __________ of the new elements they create.

Molecular Models

Show the shape and appearance of the arrangement of atoms in a compound.

Element Key

Shows the element's name, chemical symbol, atomic number, and atomic mass.

Ductility

The ability of a substance to be pulled into thin wires.

Semiconductor

The ability of a substance to conduct heat and electricity under certain conditions. At high temperatures, it conducts electricity as well as metals do; at low temperatures, it doesn't conduct electricity well. It is useful in computers, televisions, and other electronic devices.

Ionic Bond

The attraction between positively and negatively charged ions in an ionic compound (metals and nonmetals). The atoms will transfer one or more electrons to another to form the bond. Each atom is left with a complete outer shell. It forms between a metal ion with a positive charge and a nonmetal ion with a negative charge.

Actinide Series

The bottom row of the transition elements at the bottom of the periodic table.