Q:

What are the horizontal rows of the periodic table called?

A:

Quick Answer

On the periodic table, the seven horizontal rows are called periods. On the left-hand side of the periodic table, the row numbers are given as one through seven. Moving across a period from left to right, the atomic number of the elements increases.

Continue Reading

Full Answer

Rows six and seven contain elements called transition elements, which are subdivided into the actinide and lanthanide series. While the elements numbered 58 through 71 are the lanthanide series, elements with the numbers 90 through 103 are the actinide series.

The vertical columns on this table are called groups. Groups are sometimes called families because the elements in them share certain physical and chemical properties. In the older system, these groups were given the Roman numerals I through VIII. In the new system, they are designated as groups 1 through 18.

Learn more about Atoms & Molecules

Related Questions

  • Q:

    What does the periodic table tell us?

    A:

    The Periodic Table offers basic information about each one of the known chemical elements. Each element has its own box in the table, and these boxes include the element's atomic number, atomic weight and chemical symbol. An element's position on the table indicates which elements share its basic properties.

    Full Answer >
    Filed Under:
  • Q:

    Where is tungsten found on the periodic table?

    A:

    Tungsten is number 74 on the Periodic Table of Elements. It is located between tantalum, number 73, and rhenium, 75. On the periodic table, the elements are categorized in rows by "period," which indicates each element's number of atomic orbitals; tungsten is in the sixth period.

    Full Answer >
    Filed Under:
  • Q:

    Why do atoms get smaller across a period?

    A:

    Moving across periods on the periodic table from left to right, the atoms tend decrease in radius size because each atom has more protons than the atom before it, meaning there is more of an attractive force in the nucleus that pulls the electrons closer to the center. Even though there are both more protons and electrons, the attractive force of the protons wins out and makes the radius of the entire atom smaller.

    Full Answer >
    Filed Under:
  • Q:

    How does electronegativity vary within groups and across periods?

    A:

    Electronegativity tends to decrease moving down a group and tends to increase traversing left to right across periods. Electronegativity tends to decrease when moving down a group because the elements' atomic radii increase, moving any reaction further from the protons in the nucleus. Electronegativity tends to increase moving right across periods because it becomes easier to gain electrons rather than lose them.

    Full Answer >
    Filed Under:

Explore