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3 years ago

How many periods are on the periodic table?

Chemistry

2 answers:

vlada-n [284]3 years ago

8 0

Seven periods are on the periodic table going horizontally across the periodic table.

Julli [10]3 years ago

6 0

I don't know if this is right, but I believe there is seven.

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From top to bottom in most groups of elements atomic radii tend to

kogti [31]

As you go down a group on the periodic table, atomic radii tend to increase because elements with larger atomic numbers have more occupied electron levels which take up more space surrounding the nucleus.

I hope this helps.

3 0

4 years ago

A sample with a molar mass of 34.00 g/mol is found to consist of 5.9783% Hydrogen and 94.0217% oxygen. Find it’s molecular formu

kozerog [31]

Answer:

The formula is H202 (hydrogen peroxide, known as hydrogen peroxide)

Explanation:

100%----34g

5, 9783%---X= (5, 9783%x 34g)/100% =2 g

1g---1 atom of H

2g----x= 2g x 1 atom of H/1g = 2 atom of H

100%----34g

94, 0217%---X= (94,0217%x 34g)/100% =32 g

16g---1 atom of 0

32g----x= 32g x 1 atom of 0/16g = 2 atom of 0

5 0

3 years ago

What ion (cation or anion and charge) do the halogen group (17) form to fulfill the octet

Dafna11 [192]

Answer:

option B= anion (-1)

Explanation:

The halogens are present in the P- block of periodic table. There are thirty five elements present in p-block. The halogens are present in group seventeen. Their are seven electrons are present in valance sheet. All halogens require one electron to complete the octet and form anion carry -1 charge.

Halogens include following elements:

Fluorine, chlorine, bromine, iodine and astatine.

The halogens mostly form single bond with the other elements by gaining one electron and -1 charge. These are most reactive non-metals.

Properties of some halogen elements:

Fluorine:

1. It is yellow in color.

2. It is flammable gas.

3. It is highly corrosive.

4. Fluorine has pungent smell.

5. It's reactions with all other elements are vigorous except neon, oxygen, krypton and helium.

Chlorine:

1. It is greenish-yellow irritating gas.

2. Its melting point is 172.2 K.

3. Its boiling point is 238.6 K.

4. It is disinfectant and can kill the bacteria.

5. It is also used in manufacturing of paper, paints and textile industries.

Iodine:

1. It is present in solid form.

2. It is crystalline in nature.

3. It is very corrosive and has pungent odor.

4. It can not react with oxygen and nitrogen.

6 0

3 years ago

Gallium has two naturally occurring isotopes: 69ga with a mass of 68.9256 amu and a natural abundance of 60.11% and 71ga. use th

Nataly [62]

There are two naturally occurring isotopes of gallium: mass of Ga-69 isotope is 68.9256 amu and its percentage abundance is 60.11%, let the mass of other isotope that is Ga-71 be X, the percentage abundance can be calculated as:

%Ga-71=100-60.11=39.89%

Atomic mass of an element is calculated by taking sum of atomic masses of its isotopes multiplied by their percentage abundance.

Thus, in this case:

Atomic mass= m(Ga-69)×%(Ga-69)+X×%(Ga-71)

From the periodic table, atomic mass of Ga is 69.723 amu.

Putting the values,

$69.723 amu=(68.9256 amu)(\frac{60.11}{100})+X(\frac{39.89}{100})$