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Otrada [13]
3 years ago
12

Signals from the make skeletal muscles move. A. Nervous system B.

Chemistry
1 answer:
Artemon [7]3 years ago
7 0

Answer:

Signals from the A. Nervous system make the skeletal muscles move.

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Which one of the following statements about mixtures is correct [2] [3] The different substances in a mixture are always in a de
aivan3 [116]

Answer: Option (4) is the correct answer.

Explanation:

A mixture is defined as a substance that contains two or more different substance that are physically mixed with each other.

If solute particles are evenly distributed in a solvent then it is known as a homogeneous mixture.

For example, salt dissolved in water is a homogeneous mixture.

If solute particles are unevenly distributed into the solvent then it is known as a heterogeneous mixture.

For example, sand in water is a heterogeneous mixture.

Thus, we can conclude that the statement a mixture must contain at least two different substances, is correct about mixtures.

4 0
3 years ago
State general trend for metal properties as you go left to right across a period
qwelly [4]

Periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of a certain element, including its size and its electronic properties. Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character. Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element's properties. These trends exist because of the similar atomic structure of the elements within their respective group families or periods, and because of the periodic nature of the elements.

Electronegativity Trends

Electronegativity can be understood as a chemical property describing an atom's ability to attract and bind with electrons. Because electronegativity is a qualitative property, there is no standardized method for calculating electronegativity. However, the most common scale for quantifying electronegativity is the Pauling scale (Table A2), named after the chemist Linus Pauling. The numbers assigned by the Pauling scale are dimensionless due to the qualitative nature of electronegativity. Electronegativity values for each element can be found on certain periodic tables. An example is provided below.


From left to right across a period of elements, electronegativity increases. If the valence shell of an atom is less than half full, it requires less energy to lose an electron than to gain one. Conversely, if the valence shell is more than half full, it is easier to pull an electron into the valence shell than to donate one.

From top to bottom down a group, electronegativity decreases. This is because atomic number increases down a group, and thus there is an increased distance between the valence electrons and nucleus, or a greater atomic radius.

Important exceptions of the above rules include the noble gases, lanthanides, and actinides. The noble gases possess a complete valence shell and do not usually attract electrons. The lanthanides and actinides possess more complicated chemistry that does not generally follow any trends. Therefore, noble gases, lanthanides, and actinides do not have electronegativity values.

As for the transition metals, although they have electronegativity values, there is little variance among them across the period and up and down a group. This is because their metallic properties affect their ability to attract electrons as easily as the other elements.

According to these two general trends, the most electronegative element is fluorine, with 3.98 Pauling units.



6 0
3 years ago
Consider these elements: p, ca, si, s, ga.<br> a. write the electron configuration for each element
dimulka [17.4K]
Method:

1) Find the atomic number in a periodic table: the number of electrons equal the atomic number

2) Use Aufbau rule

Element     atomic number       electron configuration
<span>
P                15                            1s2 2s2 2p6 3s2 3p3

Ca              20                            </span><span><span>1s2 2s2 2p6 3s2 3p6 4s2

</span>Si                14</span><span>                            1s2 2s2 2p6 3s2 3p2

S                 16</span><span><span>                            1s2 2s2 2p6 3s2 3p4

</span>Ga               31.                   </span><span><span>        1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p</span>       </span>
7 0
3 years ago
What does the 3 indicate in 1s22s22p63s1?
Dahasolnce [82]
The 3 indicates the third electron shell. (Which has only 1 electron in it in this configuration)

Hope this helps! :)
6 0
3 years ago
Read 2 more answers
25. In the investigation shown the changes in heat of the copper is greater than the change in the heat of the water. What error
forsale [732]

Answer:

Heat lost to the surroundings

Heat lost to the thermometer

Explanation:

All changes in heat, or energy, can be explained. Many of the reactions or changes we see in the world involve the conversion of energy. For example as we heat up a substance (eg. water), the amount of energy we put in should give us an exact temperature. However, this is a "perfect world" scenario, and does not occur in real life. Whenever heat is added to a substance like water, we always need to account for the energy that is going to be lost. For example, heat lost to evaporation or even the effect of measuring the temperature with a thermometer (the introduction of anything including a thermometer will affect the temperature).

3 0
3 years ago
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