(21) Solids can be divided in to two distinct classes.
1) Crystalline solids
2) Amorphous solids
Crystalline solids have the following fundamentals properties.
1. They have characteristic geometrical shape.
2. They have highly ordered three-dimensional arrangements of particles.
3. They are bounded by PLANES or FACES
4. Planes of a crystal intersect at particular angles.
5. They have sharp melting and boiling points.
Copper Sulphate (CuSO4), NiSO4, Diamond, Graphite, NaCl, Sugar etc
Solids that don’t have a definite geometrical shape are known as Amorphous Solids.
1. In these solids particles are randomly arranged in three dimension.
2. They don’t have sharp melting points.
3. Amorphous solids are formed due to sudden cooling of liquid.
4. Amorphous solids melt over a wide range of temperature
Coal, Coke, Glass, Plastic, rubber etc(22) Matter can exist in one of three main states: solid, liquid, or gas.
- Ice to water - Ice melts back into water when it is left out at temperatures above the freezing point of 32 degrees.
- Rocks to lava - Rocks in volcanoes can be heated until they are molten lava.
- Water to steam - Water is vaporized when it is boiled on the stove to cook some pasta, and much of it forms into a thick steam.
- Water evaporates - Water evaporates from a puddle or a pool during a hot summer’s day.
- Water vapor to ice - Water vapor transforms directly into ice without becoming a liquid, a process that often occurs on windows during the winter months.
- Physical vapor to film - Thin layers of material known as "film" are deposited onto a surface using a vaporized form of the film.
(27) Properties of solid are:
retains a fixed volume and shape rigid - particles locked into place
not easily compressible little free space between particles
does not flow easily
rigid - particles cannot move/slide past one
answers of chapter 6 are in progress
(28) There are three parts of an atom: protons, neutron, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons possess no net charge.
Electrons are the smallest parts of the atom. They are the most numerous of the three. It has no known components or substructure, so it is an elementary particle.
The proton is the part of an atom that helps to form the nucleus and has a positive charge. Protons must have an equal number of neutrons except int eh hydrogen atom where a single proton exists on its own.
A neutron is the part of an atom that holds no charge. Neutrons and protons occur in equal numbers in stable atoms except in hydrogen. Protons and neutrons are often referred to together as nucleons. If there are more neutrons than protons, then the atom is considered an isotope. If an neutron becomes free of its proton, then it becomes unstable, undergoes beta decay, and will disintegrate in an average of 15 minutes. The neutron is also important in nuclear chain reactions: both natural and artificial.
(29) There are three parts of an atom: protons, neutron, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons possess no net charge.
(30) The atomic number is the number of protons in an atom of an element. In our example, krypton's atomic number is 36. This tells us that an atom of krypton has 36 protons in its nucleus.
(31) The two parts of a nucleus are the proton and the neutron.
(32) If you know the mass number and atomic number of the
atom, the number of neutrons is just the difference between them. For
example, in a carbon-13 atom, the atomic number is six and the mass number is thirteen, so the number of neutrons is seven.
Best of Luck
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