Chapter 6 The Periodic Table
Solid at room temperature
Black writing
The periodic table is divided into sections, or blocks, that correspond to the highest occupied sublevels.The s block contains the elements in Groups 1A and 2A and helium. The p block contains the elements in Groups 3A, 4A, 5A, 6A, 7A, and 8A. The transition metals belong to the d block, and the inner transition metals belong to the f block.
Blocks of Elements
Group 1A
Alkali metals
Group 2A
Alkaline earth metals
Are elements with similar properties found in the rows (periods) or columns (groups) of the modern periodic table?
Elements with similar properties are found in the columns, or groups, of the modern periodic table.
German chemist, ____ __________, classified elements into ______.
J.W. Dobereiner, triads
An ion
an atom or groups of atoms that has a positive or negative charge.
An ion with a negative charge is an
anion
Use the distance between nuclei to estimate
atomic size
Positive and negative ions form when electrons are transferred between
atoms
One way to think about atomic size is to is to look at the molecules that form when
atoms of the same element are joined to one another
liquid at room temperature
blue writing
An ion with a positive charge is a
cation
In one decade (1765-1775) chemists discovered _____ new elements.
five
Not found in nature
gray writing
Triads
groups of three, three elements with similar properties
Does atomic size increase or decrease as you move down a group?
increase
As the atomic size increases within a group, the charge on the nucleus
increases and the number of occupied energy levels increases.
The energy required to remove an electron from an atom is
ionization energy
An atom is electronically neutral because it has equal numbers of
protons and electrons
The energy required to remove the first electron from an atom is
the first ionization energy
The increase in positive charge draws electrons closer to
the nucleus
Atomic radius
one-half of the distance between the nuclei of two atoms of the same element when the atoms are joined.
As the number of elements increase, chemist looked for new ways to
organize them
The atomic radius is usually measured in
picometers (pm)
One element in each triad tends to have __________ with values that fell midway between those of the other two elements.
properties
Gases at room temperature
red writing
Elements can be sorted into
representative elements, transition metals, or inner transition metals based on their electron configuration
Chlorine, bromine, and iodine may look different, but they have very
similar chemical properties.
The periodic table usually displays the _______ and _______ ___ ____ _________, along with information about the ________ of their atom
symbols, names of the elements, structure
Does a cation have a net positive charge or a net negative charge?
positive
Only ___ elements were identified in 1700
13
Does atomic size increase or decrease as you move across a period?
Decrease
A Russian chemist and teacher who published a table of the elements. Wrote the properties of each element on a separate card, then moved them around until he found an organization that worked. Chose to write the elements into a table.
Dmitri Mendeleev
What can you learn about each element from the periodic table?
Element's name, symbol, atomic number, atomic mass, and electron configuration
Group 7A
Halagens
The elements are arranged according to repeating properties, the table was organized by increasing atomic mass. Arranged elements with similar properties in the same row, left spaces in the table because he knew that bromine belonged with chlorine and iodine. He predicted the properties of the missing elements.
Mendeleev's Periodic Table
Properties are similar to both metals and nonmetals. Under some conditions ________ act like metals and other conditions they act like nonmetals.
Metalloids
Groups 1A through 7A are ________________ ___________ because they display a wide range of physical and chemical properties. Some of these elements are metals, some nonmetals, some metalloids. Most are solids, few gases, and one liquid. The s and p sublevels of the highest occupied energy level are not filled.
Representative Elements
The rate of discovery increased as chemists started using the
Scientific Method
What does the period an element is located in tell you about that element's electron configuration? What does the group tell you?
The period tells you the highest occupied principal energy level.The group number is equal to the number of electrons in the highest occupied energy level.
Is there more variety of properties among metals or among nonmetals?
The properties of metals are more common. There is more variety among the properties of nonmetals.
A few elements, including copper, silver, and gold have been known for
Thousands of years
The periodic table is based on atomic number, not atomic mass. There are seven periods in the table. Each period corresponds to a principal energy number. There are more elements in higher-numbered periods because there are more orbitals in higher energy levels. The properties of each of the elements within a period change as you move across a period from left to right. The pattern of properties within a period repeats as you move from one period to the next.
Today's Periodic Table
The B groups elements separate the left side of the A group from the right side of the A group. Two different types of _________ elements- ____________ metals and inner ______________ metals. Usually displayed in the main body of the periodic table. The highest occupied s sublevel and a nearby d sublevel contain electrons. The inner _________ metals are the elements that appear below the main body of the periodic table. The highest occupied s sublevel and a nearby f sublevel generally contain electrons.
Transition elements
The charge for an anion is written as a
number followed by a minus sign
The charge for a cation is written as a
number followed by a plus sign
Atoms of nonmetals, tend to form ions by gaining
one or more electrons
atoms of metals tend to form ions by losing _______ __ _____ ________ from their highest occupied energy levels.
one or more electrons
Atomic size increases from
top to bottom in a group, and decreases from left to right across a period.
Chlorine, bromine, and iodine form one
triad
What type of element tends to form cations?
Metals
Why was it important for scientists to find a logical way to organize the elements?
Finding a logical way to organize the elements made it possible for scientists to determine how many elements they were looking for.
Why was Mendeleev's periodic table an improvement over Dobereiner's triad classification system and other earlier systems?
Mendeleev's periodic table could encompass all known elements and accurately predicted the existence and properties of undiscovered elements.
Across a period, the properties of elements become less metallic and more nonmetallic. About 80% of elements are _____. These elements are generally good conductors of heat and electric current. Usually have high sheen- caused by the _______'s ability to reflect light. All _______ are solids at room temperature except for mercury. Many are ductile which means that they can be drawn into wires. They are also malleable,meaning the can be hammered into thin sheets without breaking.
Metals
The sand p sublevels are completely filled with electrons for
Noble gases
There is a greater variation in physical properties among _______ than among metals. Most are gases at room temperature, including oxygen and nitrogen. A few are solids, and one is a dark red liquid (bromine). The variation makes it difficult to give them one set of general properties. They are poor conductors of heat and electric current, Carbon is the only exception when its in the form of graphite. Solid _______ tend to be brittle. meaning they will shatter if hit with a hammer.
Nonmetals
What type of element tends to form anions?
Nonmetals
First ionization energy tends to decrease from top to bottom within a ______ and increase from left to right across a ________.
group, period
