Periods in Periodic Table (Explained with Images)

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

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:

Group	1	18
Atomic no.	1	2
Element	H	He

Period 2 and 3: Short period

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:

Group	1	2	13	14	15	16	17	18
Atomic no.	3	4	5	6	7	8	9	10
Element	Li	Be	B	C	N	O	Fl	Ne

Period 3 elements:

Group	1	2	13	14	15	16	17	18
Atomic no.	11	12	13	14	15	16	17	18
Element	Na	Mg	Al	Si	P	S	Cl	Ar

Period 4 and 5: Long period

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:

Group	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
Atomic no.	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36
Element	K	Ca	Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Sc	Br	Kr

Period 5 elements:

Group	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
Atomic no.	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
Element	Rb	Sr	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe

Period 6 and 7: Longest period

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:

Group	1	2	3															4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
Atomic no.	55	56	57	58	59	60	61	62	63	64	65	66	67	68	69	70	71	72	73	74	75	76	77	78	79	80	81	82	83	84	85	86
Element	Cs	Ba	La	Ce	Pr	Nd	Pm	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb	Lu	Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg	Tl	Pb	Bi	Po	At	Rn

Period 7 elements:

Group	1	2	3															4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
Atomic no.	87	88	89	90	91	92	93	94	95	96	97	98	99	100	101	102	103	104	105	106	107	108	109	110	111	112	113	114	115	116	117	118
Element	Fr	Ra	Ac	Th	Pa	U	Np	Pu	Am	Cm	Bk	Cf	Es	Fm	Md	No	Lr	Rf	Db	Sg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og

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