I need it for science homework, and many websites I've checked say different things.
2006-10-26 13:36:07 · 5 answers · asked by dalgirl990 2 in Science & Mathematics ➔ Chemistry
26
Atomic numbers
43
61
95-118
how every some elements that occur naturally need to me man-made if you're going to use it (example francium and astatine) because they are incredibly rare (only about 28g of astatine occurs naturally in earth's cruse)
2006-10-26 13:39:20 · answer #1 · answered by Beef 5 · 0⤊ 0⤋
as far as i know to the best of my knowledge officially as of from 2010, there are 118 known elements. Of these 118 elements, 98 occur naturally on Earth, so the answer to your question in that respect would be, 20 man-made elements.
2015-07-17 16:38:15 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Tc. Pm, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Fr, Db, Sg, Bh, Hs, Mt, Ds, Rg, and unnamed 112, 114, 115, 116, and 118.
So this makes 26.
2006-10-26 13:39:34 · answer #3 · answered by Alan Turing 5 · 0⤊ 0⤋
They are technetium (at. no. 43), promethium (at. no. 61), astatine (at. no. 85), francium (at. no. 87), and the transuranium elements (at. no. 93 and beyond in the periodic table, 93-118).
2006-10-26 13:49:34 · answer #4 · answered by Dr. J. 6 · 0⤊ 0⤋
at least 26
2006-10-26 13:44:38 · answer #5 · answered by karpflover 2 · 0⤊ 0⤋