Chapter 6

Label where the groups are located on the periodic table

-Alkali metals- metals Group 1A -Alkaline Earth Metals- metals in Group 2A -Halogens- nonmetals in Group 7A -Noble gases- elements in Group 8A -Representative elements- elements in groups 1A-7A -Transition metals- elements in Group B -Inner Transition Metals- elements below the main body of the periodic table -Metals- middle of the periodic table -Nonmetals- the upper-right corner - Metalloids- stairs in between metals and nonmetals

Trends in Ionic Size

During reactions between metals and nonmetals, metal atoms tend to lose electrons and nonmetal atoms tend to gain electrons. Cations are always smaller than the atoms from which they form, and anions are always larger than the atoms from which they form. Ionic size tends to increase from top to bottom within a group. Generally, the size of cations and anions decrease from left to right across a period. Metals that are representative elements tend to lose all of their outermost electrons during ionization. Therefore, the ion has one fewer occupied energy level For nonmetals, the ion is larger than the atom. As the number of electrons increases, the attraction of the nucleus for any one electron decreases. From left to right across a period, there is a gradual decrease in the size of the positive ions (cations), followed by a gradual decrease in the size of the negative ions (anions)

Label ionization energy on a perioidic table

First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period

Trends in Ionization Energy

First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period. As the size of the atom increases, the nuclear charge has a smaller effect on the electrons in the highest occupied energy level. Less energy is required to remove an electron from this energy level, and the first ionization energy is lower. The nuclear charge increases across the period, but the shielding effect remains constant. As a result, there is an increase in the attraction of the nucleus for an electron. Thus, it takes more energy to remove an electron from an atom

Label atomic radius on a periodic table

In general, atomic size increases from top to bottom within a group and decreases from left to right across a period

Trends in Electronegativity

In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period. Metals at the far left of the periodic table have low values. Nonmetals at the far right (excluding noble gasses) have high values. The electronegativity values among the transition metals are not as regular. Cesium is the least electronegative element because it has the least tendency to attract electrons. The most electronegative element is fluorine because it has a strong tendency to attract electrons

Modern periodic table: How is it organized? What does it look like in comparison to Mendeleevs?

In the modern periodic table, elements are arranged in order of increasing atomic number. There are 7 periods (rows) that correspond to a principal energy level. There are more elements in higher-numbered periods because there are more orbitals in higher energy levels. When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. There is one important consequence of arranging elements into a period: elements that have similar chemical and physical properties end up in the same column in the periodic table. Some modern periodic tables are color-coded to classify certain types of elements. Groups are numbered left to right 1-18.

Mendeleev's periodic table: How was it organized? What did it look like?

Mendeleev developed his periodic table before scientists knew that the atoms of each element contained a unique number of protons (atomic number). Therefore, he arranged the elements in his periodic table in order of increasing atomic mass. Using the patterns in his incomplete table, Mendeleev was able to predict the properties of elements that would later be discovered

What are the 3 classes of elements (and their properties)?

Metals- (yellow) one of a class of elements that are good conductors of heat and electric current; solid at room temperature (except for mercury [Hg]); metals tend to be ductile (can be drawn into wires), malleable, and shiny. Metals make up about 80% of elements Nonmetals- (blue) an element that tends to be a poor conductor of heat and electric current (except for carbon); nonmetals generally have properties opposite to those of metals. They are located in the upper-right corner of the periodic table (except for hydrogen). Most nonmetals are gases at room temperature. A few are solids (such as sulfur and phosphorus), which tend to be brittle. Bromine is a dark-red liquid. Metalloids- (green) an element that tends to have properties that are similar to those of metals and nonmetals. Metalloids may behave like metals or nonmetals depending on the conditions that surround it

first ionization energy

The energy required to remove the first electron from an atom

What does the periodic table tell us?

The periodic table usually displays the symbols and names of the elements, along with information about the structure of their atoms. The symbol for elements that are a solid at room temperature are in black. The symbols for gasses are in red. The symbols for the two elements that are liquid at room temperature (mercury and bromine) are in blue. The symbols for elements that are not found in nature are in gray. The background colors in squares are used to distinguish the groups of elements in the periodic table.

What are ions?

They are an atom or group of atoms that has a positive or negative charge. An atom is electrically neutral because it has equal numbers of protons and electrons, but positive and negative ions form when electrons are transferred between atoms

What are anions?

They are ions with a negative charge, meaning they gained en electron during ionization. The charge for an anion is written as a number followed by a minus sign

What are cations?

They are ions with a positive charge, meaning that they lost an electron during ionization. The charge for a cation is written as a number followed by a plus sign.

halogen

a nonmetal in Group 7A of the periodic table

ion

an atom or group of atoms that has a positive or negative charge

noble gas

an element in Group 8A of the periodic table; the s and p sublevels of the highest occupied energy level are filled

representative element

an element in an "A" group in the periodic table; as a group these elements display a wide range of physical and chemical properties. In their atoms, the s and p sublevels in the highest occupied energy level are partially filled

inner transition metal

an element in the lanthanide or actinide series; the highest occupied s sublevel and nearby f sublevel of its atoms generally contain electrons; also called inner transition element

nonmetal

an element that tends to be a poor conductor of heat and electric current; nonmetals generally have properties opposite to those of metals

metalloid

an element that tends to have properties that are similar to those of metals and nonmetals

anion

any atom or group of atoms with a negative charge

cation

any atom or group of atoms with a positive charge

alkali metal

any metal in Group 1A of the periodic table

alkaline earth metal

any metal in Group 2A of the periodic table

metal

one of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable, and shiny

transition metal

one of the Group B elements in which the highest occupied s sublevel and a nearby d sublevel generally contain electrons

atomic radius

one-half the distance between the nuclei of two atoms of the same element when the atoms are joined

electronegativity

the ability of an atom to attract electrons when the atom is in a compound

ionization energy

the energy required to remove an electron from an atom in its gaseous state

periodic law

when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties