Q: What crystals consist of molecules at the lattice points of the crystal, held together by relatively weak intermolecular forces? Read this paragraph and choose the correct option from the provided answers: 4. Molecular crystals -- Molecular crystals typically consist of molecules at the lattice points of the crystal, held together by relatively weak intermolecular forces (see Figure below ). The intermolecular forces may be dispersion forces in the case of nonpolar crystals, or dipole-dipole forces in the case of polar crystals. Some molecular crystals, such as ice, have molecules held together by hydrogen bonds. When one of the noble gases is cooled and solidified, the lattice points are individual atoms rather than molecules. In all cases, the intermolecular forces holding the particles together are far weaker than either ionic or covalent bonds. As a result, the melting and boiling points of molecular crystals are much lower. Lacking ions or free electrons, molecular crystals are poor electrical conductors. Choices: - quartz crystals - salt crystals - healing crystals - molecular crystals A:
molecular crystals

Q: What is a simple sugar such as fructose or glucose? Read this paragraph and choose the correct option from the provided answers: A monosaccharide is a simple sugar such as fructose or glucose. Fructose is found in fruits, whereas glucose generally results from the digestion of other carbohydrates. Glucose is used for energy by the cells of most organisms. Choices: - disaccharide - polysaccharides - galactose - monosaccharide A:
monosaccharide

Q: In the past, what colliding with planet earth has caused many organisms to die off? Read this paragraph and choose the correct option from the provided answers: Near-Earth asteroids have orbits that cross Earth's orbit. This means that they can collide with Earth. There are over 4,500 known near-Earth asteroids. Small asteroids do sometimes collide with Earth. An asteroid about 510 m in diameter hits about once per year. Five hundred to a thousand of the known near-Earth asteroids are much bigger. They are over 1 kilometer in diameter. When large asteroids hit Earth in the past, many organisms died. At times, many species became extinct. Astronomers keep looking for near-Earth asteroids. They hope to predict a possible collision early so they can to try to stop it. Choices: - acid rain - meteorites - the Sun - asteroids A:
asteroids

Q: The periodic table is an arrangement of the elements in order of increasing what? Read this paragraph and choose the correct option from the provided answers: Summary The periodic table is an arrangement of the elements in order of increasing atomic number. Elements that exhibit similar chemistry appear in vertical columns calledgroups (numbered 118 from left to right); the seven horizontal rows are calledperiods. Some of the groups have widely used common names, including thealkali metals (group 1) and the alkaline earth metals (group 2) on the far left, and the halogens (group 17) and the noble gases (group 18) on the far right. The elements can be broadly divided into metals, nonmetals, and semimetals. Semimetals exhibit properties intermediate between those of metals and nonmetals. Metals are located on the left of the periodic table, and nonmetals are located on the upper right. They are separated by a diagonal band of semimetals. Metals are lustrous, good conductors of electricity, and readily shaped (they areductile and malleable), whereas solid nonmetals are generally brittle and poor electrical conductors. Other important groupings of elements in the periodic table are the main group elements, the transition metals, the lanthanides, and the actinides. Choices: - gravity numbers - metallic numbers - negative numbers - atomic numbers A:
atomic numbers