Two atoms of hydrogen combine with one atom of oxygen to form a molecule of water.

两个氢原子和一个氧原子结合组成一个水分子。

《牛津词典》

A molecule of water consists of two atoms of hydrogen and one atom of oxygen.

水分子由两个氢原子和一个氧原子构成。

《牛津词典》

At some point, you will cut the magnet so small that you will have cut down to the size of a single atom.

从某个方面看，你会把磁体切到如此之小，小到只有一个单原子那么大。

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The researchers found the presence of carbon thirteen, a version of the carbon atom that is usually found in space.

VOA: special.2009.09.30

Let's look at the energetics of one of those electrons crashing into a hydrogen atom inside the gas tube.

我们一起来考察一下,其中的一个电子的能量,在阴极射线管中,撞击到氢原子上。

麻省理工公开课 - 固态化学导论课程节选

OK, then it says draw a single bond from each surrounding atom to the central atom, and subtract two valence electrons.

后将中心原子与其相邻原子之间,连上单键，然后减掉2个价电子。

麻省理工公开课 - 固态化学导论课程节选

They were structurally similar to cytisine in many ways, sharing the location of a nitrogen atom in a particular place on a pair of bicycle-like carbon rings.

FORBES: Tobacco-Free

He found a 17-year-old paper written by University of Maryland researcher Paul Mazzochi that mentioned how moving a nitrogen atom in a morphine molecule caused its morphinelike properties to disappear--and also made it poisonous, just like nicotine.

FORBES: Tobacco-Free

These are an amine group, an acid group (hence the name), a hydrogen atom, and a fourth chemical group that can be any one of 20 different clusters of atoms.

ECONOMIST: Folding stuff