User M.A.R.

239

votes

3

answers

33k

views

Why is gold golden?

Jun 5 '20 at 14:45 Mathew Mahindaratne 33.7k

220

votes

1

answer

65k

views

Why can we smell copper?

everyday-chemistry metal transition-metals smell

Apr 17 '18 at 9:42 Archer 4,948

176

votes

8

answers

156k

views

Can an atom have more than 8 valence electrons? If not, why is 8 the limit?

physical-chemistry electrons electronic-configuration valence-bond-theory

Dec 15 '17 at 20:44 Oscar Lanzi 33.2k

113

votes

7

answers

68k

views

Is a negative pH level physically possible?

acid-base equilibrium ph

Aug 10 '19 at 8:56 CommunityBot 1

103

votes

5

answers

81k

views

How do you melt metals with super high melting points?

melting-point

Apr 19 at 17:04 andselisk♦ 33.7k

89

votes

2

answers

35k

views

What is Bent's rule?

bond orbitals hybridization stereochemistry valence-bond-theory

Oct 21 '16 at 22:54 CommunityBot 1

87

votes

7

answers

126k

views

Why is the 2s orbital lower in energy than the 2p orbital when the electrons in 2s are usually farther from the nucleus?

energy electrons quantum-chemistry orbitals

Dec 24 '19 at 6:20 CommunityBot 1

78

votes

4

answers

37k

views

Bonding in diatomic C2, a carbon-carbon quadruple bond?

theoretical-chemistry bond molecular-orbital-theory covalent-compounds

Jun 13 '20 at 14:57 Mathew Mahindaratne 33.7k

66

votes

4

answers

31k

views

Why do elements in columns 6 and 11 assume 'abnormal' electron configurations?

orbitals electronic-configuration transition-metals

Dec 24 '19 at 6:28 CommunityBot 1

65

votes

4

answers

21k

views

How does Walter White make pure crystal meth using a non-stereospecific reaction?

reaction-mechanism stereochemistry chemistry-in-fiction

Mar 3 at 12:33 madscidiysam 1

62

votes

4

answers

54k

views

How can one explain niobium’s weird electronic configuration?

electronic-configuration transition-metals

Aug 22 '19 at 15:31 shibu sarkar 1

58

votes

4

answers

224k

views

Why add water first then acid?

acid-base experimental-chemistry safety

Aug 21 at 16:44 Buck Thorn♦ 18k

56

votes

3

answers

10k

views

Why do we write NH3?

inorganic-chemistry nomenclature

Feb 11 '16 at 17:47 CommunityBot 1

55

votes

6

answers

11k

views

The last element's atomic number

physical-chemistry atoms nuclear elements

Jul 24 at 19:47 AC DeBlanc 21

52

votes

2

answers

55k

views

What makes some metals melt at higher temperature?

melting-point metal

Dec 24 '19 at 7:10 Mathew Mahindaratne 33.7k

50

votes

1

answer

10k

views

Why does menthol (e.g. peppermint) feel cool to the tongue?

biochemistry

Oct 19 '15 at 14:04 CommunityBot 1

48

votes

5

answers

8k

views

How can antibonding orbitals be more antibonding than bonding orbitals are bonding?

bond quantum-chemistry molecular-orbital-theory

Jun 10 at 17:32 Mathew Mahindaratne 33.7k

48

votes

5

answers

78k

views

Why does bond angle decrease in the order H2O, H2S, H2Se?

bond periodic-trends hybridization molecular-structure

Jan 21 '19 at 23:29 Andrew 7,944

46

votes

4

answers

51k

views

Why do the names of most chemical elements end with -um or -ium?

nomenclature elements

Mar 21 '17 at 14:52 CommunityBot 1

46

votes

5

answers

47k

views

Is there any substance that's a 4-4-4 on the NFPA diamond?

safety toxicity

Apr 29 at 16:21 Buttonwood 21k

43

votes

3

answers

8k

views

Carbon atoms at the edge of a diamond

crystal-structure hybridization

Apr 22 '19 at 14:43 Jaimes Beam 1

42

votes

1

answer

88k

views

Differences between phenols and alcohols

organic-chemistry alcohols phenols

Nov 5 '19 at 23:00 CommunityBot 1

42

votes

4

answers

8k

views

What is more acidic: D3O+ in D2O or H3O+ in H2O and why?

acid-base kinetics isotope

Jun 19 '19 at 22:28 Mathew Mahindaratne 33.7k

41

votes

4

answers

47k

views

The reason behind the steep rise in pH in the acid base titration curve

acid-base ph

Oct 25 '20 at 7:08 G M 8,769

41

votes

1

answer

5k

views

Why is methane's molecular formula conventionally "CH₄", while water is "H₂O" (among others)?

nomenclature notation

Feb 21 '15 at 22:27 ron 80.8k

40

votes

3

answers

14k

views

Why do impurities lower the melting point of an isolated substance?

thermodynamics mixtures melting-point

Dec 14 '15 at 12:19 M.A.R. 9,918

40

votes

3

answers

5k

views

Do molecules with bridges through rings exist?

organic-chemistry bond synthesis molecular-structure molecules

Jun 6 at 18:03 Mathew Mahindaratne 33.7k

40

votes

2

answers

56k

views

Why do SN1 and SN2 reactions not occur at sp2 centres?

organic-chemistry nucleophilic-substitution

Oct 25 '18 at 23:48 orthocresol♦ 61.4k

39

votes

2

answers

22k

views

How can the dipole moment of carbon monoxide be rationalised by molecular orbital theory?

bond theoretical-chemistry molecular-orbital-theory

Feb 6 '18 at 23:12 Jingjie YANG 313

39

votes

3

answers

108k

views

What is the inert pair effect?

inorganic-chemistry quantum-chemistry orbitals periodic-trends relativistic

Mar 1 '18 at 18:48 pentavalentcarbon 7,181

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Why is gold golden?

Why can we smell copper?

Can an atom have more than 8 valence electrons? If not, why is 8 the limit?

Is a negative pH level physically possible?

How do you melt metals with super high melting points?

What is Bent's rule?

Why is the 2s orbital lower in energy than the 2p orbital when the electrons in 2s are usually farther from the nucleus?

Bonding in diatomic C2, a carbon-carbon quadruple bond?

Why do elements in columns 6 and 11 assume 'abnormal' electron configurations?

How does Walter White make pure crystal meth using a non-stereospecific reaction?

How can one explain niobium’s weird electronic configuration?

Why add water first then acid?

Why do we write NH3?

The last element's atomic number

What makes some metals melt at higher temperature?

Why does menthol (e.g. peppermint) feel cool to the tongue?

How can antibonding orbitals be more antibonding than bonding orbitals are bonding?

Why does bond angle decrease in the order H2O, H2S, H2Se?

Why do the names of most chemical elements end with -um or -ium?

Is there any substance that's a 4-4-4 on the NFPA diamond?

Carbon atoms at the edge of a diamond

Differences between phenols and alcohols

What is more acidic: D3O+ in D2O or H3O+ in H2O and why?

The reason behind the steep rise in pH in the acid base titration curve

Why is methane's molecular formula conventionally "CH₄", while water is "H₂O" (among others)?

Why do impurities lower the melting point of an isolated substance?

Do molecules with bridges through rings exist?

Why do SN1 and SN2 reactions not occur at sp2 centres?

How can the dipole moment of carbon monoxide be rationalised by molecular orbital theory?

What is the inert pair effect?