Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Carbon is a very common ingredient of matter because it can combine with itself and with many other elements. It can form a great diversity of compounds, ranging in size from just a few atoms to thousands of atoms. There are millions of known carbon compounds, and carbon is the only element that can form so many different compounds. Carbon is a nonmetal in group 14 of the periodic table. Like other group 14 elements, carbon has four valence electrons. Valence electrons are the electrons in the outer energy level of an atom that are involved in chemical bonds. The valence electrons of carbon are shown in the electron dot diagram in the Figure 1.1. Q: How many more electrons does carbon need to have a full outer energy level? A: Carbon needs four more valence electrons, or a total of eight valence electrons, to fill its outer energy level. A full outer energy level is the most stable arrangement of electrons. Q: How can carbon achieve a full outer energy level? A: Carbon can form four covalent bonds. Covalent bonds are chemical bonds that form between nonmetals. In a covalent bond, two atoms share a pair of electrons. By forming four covalent bonds, carbon shares four pairs of electrons, thus filling its outer energy level and achieving stability. A carbon atom can form covalent bonds with other carbon atoms or with the atoms of other elements. Carbon often forms bonds with hydrogen. Compounds that contain only carbon and hydrogen are called hydrocarbons. Methane (CH4 ), which is modeled in the Figure 1.2, is an example of a hydrocarbon. In methane, a single carbon atom forms covalent bonds with four hydrogen atoms. The diagram on the left in the Figure 1.2 shows all the shared valence electrons. The diagram on the right in the Figure 1.2, called a structural formula, represents each pair of shared electrons with a dash (-). Methane (CH4 ) Carbon can form single, double, or even triple bonds with other carbon atoms. In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons. Examples of compounds with these types of bonds are represented by the structural formulas in the Figure 1.3. Q: How many bonds do the carbon atoms share in each of these compounds? A: In ethane, the two carbon atoms share a single bond. In ethene they share a double bond, and in ethyne they share a triple bond.
carbon forms triple bonds with other carbon atoms in the compound named