Periods in Periodic Table (Explained with Images)

Periods Periodic Table

Periods in periodic table are the horizontal rows on the periodic table. There are a total 7 horizontal rows on the periodic table, that means the periodic table has 7 periods.

  • Period 1: Shortest period (having 2 elements)
  • Period 2 and 3: Short period (having 8 elements each)
  • Period 4 and 5: Long period (having 18  elements each)
  • Period 6 and 7: Longest period (having 32 elements each)

Let’s discuss each of these periods of periodic table one by one.

Period 1: Shortest period

period 1 elements

The 1st period of the periodic table is known as the shortest period.

Period 1 is the shortest period because it has only 2 elements in it.

The number of shell present in the period 1 elements is 1.

Elements of period 1 are given in the table below.

Period 1 elements:

Group118
Atomic no.12
ElementHHe

Period 2 and 3: Short period

period 2 and 3 elements

The 2nd period and the 3rd period of the periodic table are known as the short periods.

Period 2 and period 3 are the short period because they have 8 elements in it.

Period 2 elements have 2 energy shells while period 3 elements have 3 energy shells.

Elements of period 2 and period 3 are given in the tables below.

Period 2 elements:

Group12131415161718
Atomic no.345678910
ElementLiBeBCNOFlNe

Period 3 elements:

Group12131415161718
Atomic no.1112131415161718
ElementNaMgAlSiPSClAr

Period 4 and 5: Long period

period 4 and 5 elements

The 4th period and the 5th period of the periodic table are known as the long periods.

Period 4 and period 5 are the long period because they have 18 elements in it.

Period 4 elements have 4 energy shells while period 5 elements have 5 energy shells.

Elements of period 4 and period 5 are given in the tables below.

Period 4 elements:

Group123456789101112131415161718
Atomic no.192021222324252627282930313233343536
ElementKCaScTiVCrMnFeCoNiCuZnGaGeAsScBrKr

Period 5 elements:

Group123456789101112131415161718
Atomic no.373839404142434445464748495051525354
ElementRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe

Period 6 and 7: Longest period

period 6 and 7 elements

The 6th period and the 7th period of the periodic table are known as the longest periods.

Period 6 and period 7 are the longest period because they have 32 elements in it.

Period 6 elements have 6 energy shells while period 7 elements have 7 energy shells.

Elements of period 6 and period 7 are given in the tables below.

Period 6 elements:

Group123456789101112131415161718
Atomic no.5556575859606162636465666768697071727374757677787980818283848586
ElementCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRn

Period 7 elements:

Group123456789101112131415161718
Atomic no.87888990919293949596979899100101102103104105106107108109110111112113114115116117118
ElementFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg

External resources:

  1. Period | chemistry. (n.d.). Encyclopedia Britannica. https://www.britannica.com/science/period-chemistry
  2. Period (periodic table) – Wikipedia. (2008, February 5). Period (Periodic Table) – Wikipedia. https://en.wikipedia.org/wiki/Period_(periodic_table)
  3. 6.4: Modern Periodic Table- Periods and Groups. (2016, June 24). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/06%3A_The_Periodic_Table/6.04%3A_Modern_Periodic_Table-_Periods_and_Groups
  4. Reading the Periodic Table. (n.d.). Reading the Periodic Table. http://www.csun.edu/~psk17793/G%20Chemistry/reading_the_periodic_table.htm
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