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Which type of compound often forms crystals, has high melting points, and is made from atoms with opposite charges?
ionic
Using the lesson ideas, predict what happens to particle motion, potential energy, and state when thermal energy is removed from a gas.
Particle motion (kinetic energy) decreases, potential energy decreases as attractions become more significant, and the gas may condense to liquid and then freeze to solid if enough energy is removed.
Q: What simple phrase summarizes whether substances dissolve each other (polar vs nonpolar)?
"like dissolves like"
Will oil (nonpolar) dissolve in water (polar)? Answer and explain briefly.
oil is nonpolar and water is polar, so they do not mix; nonpolar substances dissolve in other nonpolar substances.
What property (one word) describes metals that can be hammered or bent without breaking?
malleable
Explain how sodium chloride (table salt) forms an extended structure and identify the types of elements involved.
Sodium (a metal) and chlorine (a nonmetal) form ionic bonds due to opposite charges; these strong attractions create an extended crystal lattice (extended structure).
What do we call a group of atoms held together by chemical bonds that act as a unit?
molecule
Describe the energy changes (potential or kinetic) when a solid metal is heated until it melts.
Thermal energy increases particle motion (kinetic energy) and overcomes attractions (raising potential energy stored in arrangements) until the structure changes from solid to liquid.
A __________________ is Matter made of two or more different kinds of atoms joined by chemical bonds.
compound
What is a substance made of only one type of atom called?
element
How does particle attraction relate to melting and boiling points?
Stronger attraction between particles leads to higher melting and boiling points; weaker attraction leads to lower melting and boiling points.
Contrast the electrical conductivity of nonmetal solids and metals, and explain using atomic structure.
Metals conduct electricity well because electrons/charges can move easily between closely packed atoms in extended structures; nonmetal solids are poor conductors because they have low attraction between atoms and do not allow charge to move easily.
Why are many nonmetal gases poor conductors of electricity and thermal energy?
Because atoms or molecules in nonmetal gases have low attraction and large space between particles, so they cannot easily transfer charge or energy.
If an ionic compound dissolves in water, what property does the resulting solution often have?
The solution often conducts electricity well (because ions are free to move).
What type of compounds form molecules, often have low melting/boiling points, and are poor conductors?
covalent compounds
At room temperature, most metals are in which state of matter?
solid
Which type of compound (polar covalent or nonpolar covalent) is likely to form crystals and have high melting points — as in sugar?
Polar covalent compounds (sugar is polar and forms crystals with higher melting/boiling points compared to nonpolar molecules).
Why do metals generally have high melting and boiling points?
Because metal atoms are closely attracted and form extended structures, requiring more thermal energy to change state.
Explain why atoms in gases like helium have high kinetic and potential energy relative to solids.
Because gas particles have low attraction to each other and large space between particles, allowing higher motion (kinetic energy) and higher potential energy compared with particles in solids.
What state of matter are most nonpolar covalent compounds (like CO2) at room temperature?
gases