1)Compare the properties of metals nonmetals and metolliods?
2)Why can elements and compound be considered pure substance?
3)What is the difference between colloids and suspension?
1)Elements that have properties of both metals and nonmetals are called metalloids. They can be shiny or dull and their shape is easily changed. Metalloids typically conduct heat and electricity better than nonmetals but not as well as metals.....
Nonmetals, on the right side of the periodic table, are very different from metals. Their surface is dull and they are poor conductor of heat and electricity. As compared to metals, they have low density and will melt at low temperatures. The shape of a nonmetal cannot be changed easily as they tend to be brittle and will break.
2)Pure substances r those substances which r made of only one kind of PARTICLES. Now these particles can be ATOMS OR MOLECULES.
3)Particle size. From the reference, "Colloidal particles are larger than molecules but too small to be observed directly with a microscope; however, their shape and size can be determined by electron microscopy. In a true solution the particles of dissolved substance are of molecular size and are thus smaller than colloidal particles; in a coarse mixture (e.g., a suspension) the particles are much larger than colloidal particles. Although there are no precise boundaries of size between the particles in mixtures, colloids, or solutions, colloidal particles are usually on the order of 10^-7 to 10^-5 cm in size."
1) To compare the properties of metals, nonmetals, and metalloids, we can observe their characteristics:
- Metals: Generally have high electrical and thermal conductivity. They are malleable (can be hammered into sheets) and ductile (can be drawn into wires) due to their ability to form metallic bonds. Metals usually have a shiny luster, are solid at room temperature (except for mercury), and have high melting and boiling points.
- Nonmetals: Typically have low electrical and thermal conductivity. Nonmetals tend to be brittle when solid, lack metallic luster, and have lower melting and boiling points compared to metals. They can exist in various states (solid, liquid, or gas) at room temperature. Nonmetals are often good insulators.
- Metalloids: Possess properties that are intermediate between metals and nonmetals. They have moderate electrical conductivity and can behave as either conductors or insulators, depending on conditions. Metalloids tend to be brittle and have relatively lower melting and boiling points compared to metals.
To compare these properties, you can refer to the periodic table, which classifies elements as metals, nonmetals, or metalloids based on their properties. Look for the groupings on the periodic table and identify the elements within each category to explore their specific characteristics.
2) Elements and compounds can be considered pure substances because they consist of only one type of substance.
- Elements: Elements are the simplest form of matter that cannot be broken down into simpler substances by chemical means. Each element is composed of atoms that have the same number of protons in the nucleus. Examples of elements include oxygen, gold, and carbon.
- Compounds: Compounds are substances made up of two or more elements chemically bonded together in fixed ratios. They can be broken down into simpler substances through chemical reactions. The constituents of a compound are always present in the same proportion. Examples of compounds include water (H2O) and sodium chloride (NaCl).
When considering elements and compounds as pure substances, it means that their properties and chemical composition are consistent and do not vary from sample to sample. Additionally, elements and compounds have specific physical and chemical properties that separate them from mixtures.
3) Colloids and suspensions are both types of mixtures, but they differ in the size of the particles dispersed in the mixture and their stability.
- Colloids: Colloids are mixtures in which the dispersed particles are larger than individual molecules or ions but smaller than those found in suspensions. The particles in colloids do not settle out upon standing and remain evenly dispersed throughout the mixture. Colloids can exhibit the Tyndall effect, which is the scattering of light by the colloidal particles. Examples of colloids include milk, mayonnaise, and fog.
- Suspensions: Suspensions are mixtures in which larger particles are dispersed in a medium, such as a liquid or gas. The particles in suspensions are often visible and can settle out over time due to gravity or if left undisturbed. Suspensions may require stirring or shaking to disperse the particles evenly for a short period. Examples of suspensions include muddy water, sand in water, and orange juice with pulp.
In summary, colloids have smaller particles than suspensions, do not settle out over time, and exhibit the Tyndall effect, while suspensions have larger particles, can settle out, and require agitation to keep the particles dispersed.