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aliina [53]
3 years ago
12

How many elements are in the periodic table?

Chemistry
2 answers:
gogolik [260]3 years ago
5 0

There are <u>118</u> elements.

ZanzabumX [31]3 years ago
3 0
I think there’s 118 elements
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What is the oxidation number of cl− in the hypochlorite ion clo−?
mariarad [96]

Answer : The oxidation number of chlorine (Cl) is, (+1)

Explanation :

Oxidation number : It represent the number of electrons lost or gained by the atoms of an element in a compound.

Oxidation numbers are generally written with the sign (+) and (-) first and then the magnitude.

When the atoms are present in their elemental state then the oxidation number will be zero.

Rules for Oxidation Numbers :

The oxidation number of a free element is always zero.

The oxidation number of a monatomic ion equals the charge of the ion.

The oxidation number of  Hydrogen (H)  is +1, but it is -1 in when combined with less electronegative elements.

The oxidation number of  oxygen (O)  in compounds is usually -2, but it is -1 in peroxides.

The oxidation number of a Group 1 element in a compound is +1.

The oxidation number of a Group 2 element in a compound is +2.

The oxidation number of a Group 17 element in a binary compound is -1.

The sum of the oxidation numbers of all of the atoms in a neutral compound is zero.

The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

The given compound is, ClO^-

Let the oxidation state of 'Cl' be, 'x'

x+(-2)=-1\\\\x-2=-1\\\\x=+1

Therefore, the oxidation number of chlorine (Cl) is, (+1)

5 0
3 years ago
The number of nitrogen atoms in one mole of nitrogen gas are...
9966 [12]

Explanation:

The number of nitrogen atoms in one mole of nitrogen gas are <em><u>6.02214179×1023 nitrogen </u></em><em><u>atoms</u></em><em><u>.</u></em><em><u> </u></em>

<em>Hope this helps... </em>

3 0
3 years ago
Assume the recommended single dose of an antihistamine for a child weighing between 18-23 lbs is 0.75 teaspoons (tsp). if 1.00 t
blagie [28]

We are given that 1 teaspoon is equivalent to 5 mL, therefore 0.75 teaspoon is:

0.75 teaspoon * (5 mL / 1 teaspoon) = 3.75 mL

 

So the mass is density times volume:

mass = (12.5 mg/5 ml) * 3.75 mL

<span>mass = 9.375 mg</span>

7 0
3 years ago
Read 2 more answers
An alpha particle is equivalent to a _____ nucleus.
Allushta [10]
An alp-ha particle is equivalent to the nucleus of a helium atom. Helium Atom = Answer.
8 0
3 years ago
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Indicate what happens to the concentration of Pb2+ in each half cell
Taya2010 [7]

Answer:

Your questions requires diagrams of the cell to get which one is on the left or right. However, see the attached file below

The correct answer is (d) the left half-cell will decrease in concentration; and the right half-cell will increase in concentration.

Explanation:

The concentration of the Pb2+ increases in the oxidation half cell while the concentration of the Pb2+ decreases in the reduction half cell during the reaction.

In the Left Beaker (Left half cell), their is less concentration

Pb(s) ---> Pb2+(aq) + 2 e- Concentration of Pb2+(aq) increase ; Electrons going out from this side

In the Right Beaker (right half cell), their is more concentration

Pb2+(aq) + 2 e- ---> Pb(s) Concentration of Pb2+(aq) decrease ; Electrons coming in to this side

Electrons will flow from Left to Right direction.

3 0
3 years ago
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