how many elements are there in it?
118
Periodic table
The elements from atomic numbers 1 (hydrogen) through 118 (oganesson) have all been discovered or synthesized, completing seven full rows of the periodic table.
what do the alternating bands of jupiter suggest the presence of The zones' lighter color is believed to result from ammonia ice; what gives the belts their darker colors is uncertain. what is it composed of? It is mostly made of molecular hydrogen and helium in roughly solar proportions. what can you tell me about its structure? The atmosphere is classified into four layers: the troposphere, stratosphere, thermosphere and exosphere; the planet does not have a solid surface, and the lowest atmospheric layer, the troposphere, smoothly transitions into the planet's fluid interior. what is the symbol of the second chemical component mentioned above? 'He' when was it initially discovered? 1868 where is it placed in the periodic table? It is  the first in the noble gas group in the periodic table. what is it used for? It is used as a breathing gas - helium mixtures such as trimix, heliox and heliair are used for deep diving to reduce the effects of narcosis, which worsen with increasing depth. where is it abundantly found? It is the second most abundant element in the known Universe, constituting 23% of its baryonic mass. does it cause any hazards? Inhaling helium can be dangerous if done to excess, since helium is a simple asphyxiant and so displaces oxygen needed for normal respiration. how is it extracted? For large-scale use, it is extracted by fractional distillation from natural gas, which can contain as much as 7% helium. who introduced the table mentioned above? Russian chemist Dmitri Mendeleev what does the table contain? It is a tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties.
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Periodic table [SEP] Introduction
The elements from atomic numbers 1 (hydrogen) through 118 (oganesson) have all been discovered or synthesized, completing seven full rows of the periodic table. The first 94 elements, hydrogen through plutonium, all occur naturally, though some are found only in trace amounts and a few were discovered in nature only after having first been synthesized. Elements 95 to 118 have only been synthesized in laboratories, nuclear reactors, or nuclear explosions. The synthesis of elements having higher atomic numbers is currently being pursued: these elements would begin an eighth row, and theoretical work has been done to suggest possible candidates for this extension.