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Natali [406]
3 years ago
7

Why was helium absent from mendeleev's original periodic table of 1871?

Chemistry
1 answer:
34kurt3 years ago
6 0
<span>This is because it was not yet discovered during that time. Helium (noble gases) was extremely difficult to discover that time because it does not react with other elements. And now since Mendeleev had based his table on the similar properties of known elements he could not have included Helium in his table.</span>
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If the density of gold is 19.3 g/cm3 what would be the volume of 550 g of gold?​
RUDIKE [14]

Answer:

28.497 cm3

Explanation:

Formula

D=m/v

Given data:

density = 19.3g/cm3

mass = 550 g

Now we will put the values in formula:

V=m/d

V=550 g/ 19.3 g/cm3  = 28.497 cm3

So the volume of gold is 28.497 cm3.

7 0
3 years ago
Describe the function of the PNS and the CNS
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The peripheral nervous system<span>, or </span>PNS<span>, consists of the nerves and ganglia outside of the brain and the spinal cord. The main </span>function of the PNS<span> is to connect the central </span>nervous system<span> (</span>CNS<span>) to the limbs and organs.</span>
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The electron pair in a C-F bond could be considered Question 3 options: closer to C because carbon has a larger radius and thus
Leokris [45]

Answer:

closer to F because fluorine has a higher electronegativity than carbon

Explanation:

Electronegativity refers to the ability of an atom in a bonding situation to draw the shared electrons of the bond closer to itself.

Electronegativity increases across the period and decreases down the group. A highly electronegative atom draws the shared electron pair of a bond towards itself.

When two atoms are bonded together, the electron pair is always drawn closer to the atom that has a higher electronegativity.

Hence, the electron pair in a C-F bond could be considered closer to F because fluorine has a higher electronegativity than carbon.

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When chemicals react with each other which factors decide that a successful reaction has taken place ?
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The factors that affect the rate of a reaction are:

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3 years ago
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