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ATI TEAS SCIENCE REVIEW

PERIODIC TABLE

ATI TEAS SCIENCE – PERIODIC TABLE

Questions related to Periodic Table test your understanding of how toread the periodic table of the elements. You may also be tested onvarious properties shared by different groups of elements. Otherquestions may address atomic radii, ionization potential, andelectronegativity, based on an element’s location on the periodic table.

Let’s get started in understanding how periodic table is important onthe ATI TEAS.

ATI TEAS SCIENCE – PERIODIC TABLEREADING THE PERIODIC TABLE

The periodic table is a table of chemical elements arranged by atomic number. Here is an example:

PHOTO CREDIT: FUTURITY

ATI TEAS SCIENCE – PERIODIC TABLEREADING THE PERIODIC TABLE

The elements on the periodic table are listed in order of their atomicnumber. Some periodic tables provide the atomic mass of the elementas well:

From the periodic table, by reading the atomic number, you candetermine the number of protons and electrons in a neutral atom of anelement. The number of neutrons can also be determined if the massnumber of the atom is known.

ATI TEAS SCIENCE – PERIODIC TABLE

UNDERSTANDING PERIODS AND GROUPS

Elements of the periodic table are arranged in periodsand in groups. Periods of the periodic table are organizedhorizontally across the table in rows. In the table show,the shaded row represents a period:

PHOTO CREDIT: WIZER

Groups in the periodic table are organized vertically downthe table in columns. Groups may also be referred to asfamilies. In the table shown, the shaded column representsa group:

PHOTO CREDIT: WIZER

ATI TEAS SCIENCE – PERIODIC TABLE

UNDERSTANDING PERIODS AND GROUPS

Elements in different groups share certain properties.The alkali metals in group 1 are shiny, soft, and highlyreactive. The alkaline earth metals in group 2 arefairly soft and fairly reactive. The transition metals ingroups 3 to 12 are hard and have low to negligiblereactivity. The halogens in group 17 are extremelyreactive, whereas the noble gases in group 18 areextremely stable. Metals overall tend to be malleableand highly conductive of heat and electricity, whereasnonmetals break easily and are generally poorconductors. Metalloids, such as boron, silicon, andgermanium, have properties between those of metalsand nonmetals.

PHOTO CREDIT: FUTURITY

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ATI TEAS SCIENCE – PERIODIC TABLE

UNDERSTANDING ATOMIC RADII

The atomic radius of an atom is the measure of the distance fromthe center of the atom to its outermost orbital shell. Atoms withgreater numbers of orbital shells have larger atomic radii becausethe outermost electrons are father away from the nucleus. Thelength of the atomic radii decreases as you move from the left toright across a period (row) of the table. The length of the atomic radiiincreases as you move down a group (column of the table).

PHOTO CREDIT: SOCRATIC

ATI TEAS SCIENCE – PERIODIC TABLE

UNDERSTANDING IONIZATION POTENTIAL AND ELECTRONEGATIVITY

The term ionization energy is used to refer to the amount of energy

required for the removal of one electron from an atom. Theionization energy of an atom increases as the atomic radius of theatom decreases. This means that ionization energy increases as you

move from left to right across a period (row) of the table. It alsodecreases as you move down a group (column) of the table.

The term electronegativity is used to refer to the tendency of anatom to want to bond with other atoms by taking electrons from

those atoms. Like ionization energy, the electronegativity of an atomincreases as the atomic radius of the atom decreases. This meansthat electronegativity increases as you move from left to right across

a period (row) as atomic radius decreases, and it decreases as youmove down a group (column) of a table as the atomic radiusincreases.

PHOTO CREDIT: THOUGHT CO

ATI TEAS SCIENCE – PERIODIC TABLE

UNDERSTANDING ORBITALS

The periodic table can also show the orbitals for the elements. Anorbital is an area around the nucleus of a cell where electrons can belocated. There are four types of orbitals.

• An s orbital is the lowest level of energy and forms a symmetricalsphere around the nucleus. It can have amaximumof 2 electrons.

• A p orbital is like an hourglass shape with the nucleus at the center.The p orbital has amaximumof 6 electrons.

• D orbitals are more complex, but most look like four pear shapesconnected by the nucleus at the center. The d orbital has a maximumof 18 electrons.

• F orbitals are even more complex and are very difficult to visualize.The f orbital has amaximumof 32 electrons.

ATI TEAS SCIENCE – PERIODIC TABLEUNDERSTANDING ORBITALS

As the period numbers on the periodic table increase, the number of orbitals available also increases. Period 1 has only one orbital, s, with a maximum of 2 electrons. Period 2 elements have both an s orbital and a p orbital. Period 3 can have s, p, and d orbitals. Period 4 can have s, p, d, and f orbitals.