Answer:
C. representative elements.
Explanation:
Families 1 - 2 and 13 - 18 are called representative elements or often times, main group elements.
- Elements on the periodic table belongs to four blocks which are s, p, d and f blocks.
- Those in the s and p-blocks are the main group elements also called representative elements.
- Their outer-shell are not completely filled with electrons but their inner shell is completely filled.
Buckyball or buckminster fullerene is the third allotrope of carbon. It contains 60 carbons which are arranged in the five and six membered rings. Buckyball is the cluster of carbon atoms which are arranged in spherical shape and it forms a hollow cage.
The physical properties are:
Buckyball is made up of huge number of molecules but giant covalent bond is not exist.
The forces between the individual buckyballs are weak intermolecular forces.
The substances which are made up of buckyballs has low melting point in comparison to other allotropes of carbon as low energy is required to overcome theses intermolecular forces.
The substances which are made up of buckyballs is slippery in nature.
The solutions of buckminster fullerene are deep purple in color and upon evaporation brown residue is obtained.
Buckyball is soft in comparison to graphite and when it is compressed to less than 70 percent of its volume then, it converts into superhard form of diamond.
Answer: There is no list in your question. But the three factors in which natural selection occurs are:
1. A struggle for existence,
2. Variation and
3. Inheritance
Explanation:
Darwin’s theory of natural selection is the way in which organisms change overtime.
These changes allow organisms to become better adapted to their environment and increase their chances for survival.
The three major factors through which natural selection occurs are:
1. A struggle for existence,
2. Variation and
3. Inheritance
Darwin’s theory of natural selection will occur if the three conditions above are met and unless these factors are in place, natural selection will not occur.
<span>2AlPO4 ( aq) + 3MgCl2 (aq) -> Mg3(PO4)2 (s) + 2AlCl3 (aq) </span>
<span>Right answer is D
</span>
Answer:
- 1. Dimensions: The sheet can be cut into several smaller pieces.
- 2. Shape: the sheet can be formed into a paper ball or any other shape (using origami for example).
- 3. Color: You can use crayons to paint the sheet and change its color.
Explanation:
<em>Physical changes</em> do not change the chemical properties. They do not transform the compounds that form the substances. They do not break and or form chemical bonds.
When you change the form, the state (solid, liquid or gas), the color, you are just changing physical properties.
Only chemical changes change the compounds that form the substance. For instance, if you burn the <em>sheet of paper</em>, then you are causing a chemical change because the organic matter in the paper will react with oxygen forming CO₂ and water, but by cutting, folding, smashing, or coloring with crayons, the compounds in the<em> sheet of paper</em> do not change.
