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DIA [1.3K]
2 years ago
7

The periodic table has undergone some changes since it was first introduced. List three ways the modern periodic table differs f

rom the one first published by Mendeleev in 1869.
I have two of the three ways:
1: updating the atomic weight
2: adding newly discovered elements

However, I cannot come up with a last way the modern periodic table differs from Mendeleev's. Please help (:
Chemistry
1 answer:
Hoochie [10]2 years ago
6 0
One of the differences I can think of is that hydrogen is no longer listed as a group I element.

According to the mendeleev tables that I looked up, hydrogen is catorgrized as a group I element, along with Lithium, sodium, Potassium etc. However, nowadays, hydrogen does not belong to any groups in the periodic table. This is because there are arguments about whether hydrogen belongs to group I. Group I elements are all alkali metals, while hydrogen is not. However, some people says that hydrogen only have one outer shell electron so it should be in group I. Some people even say hydrogen should belong to group VII because it only needs one more electron in order to achieve the duplet of electrons.

Therefore as you may notice, hydrogen in modern periodic tables are put in the center of the periodic table on the top.
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A chemical reaction in which bonds are created is usually associated with ________.
Nikolay [14]

A  reaction in which bonds are created is usually associated with the Release of energy.

What are the various types of bonds?

There are three sorts of bonds:

1. Electrovalent or  electrovalent bond

2.  chemical bond

3.  dative bond

Electrovalent or electrovalent bond are formed when one or more electrons are transferred from one atom to another.

Covalent bonds are formed when the atoms during a  molecule share an equal number of electrons.

A dative bond is one in which both electrons in a shared pair come from the same atom.

Now, atoms tend to stabilize once they form chemical bonds, releasing energy within the process. Energy is released because there's a higher level of stability associated with a low energy level.

Hence, a  reaction in which bonds are created is usually associated with the release of energy.

To know more about chemical bonds go to the given link:

brainly.com/question/20584851

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4 0
1 year ago
Please help me with my science thank you!
Tatiana [17]
I cant see it maybe post it again?
4 0
2 years ago
The practice of making operations "carbon neutral" is a way to offset whatever damage is being done to the environment due to gr
Marianna [84]

Answer:

True

Explanation:

The greenhouse effect is the process whereby there is radiation from a atmosphere planet and the planet increase the temperature of the planet's surface to a temperature above normal.In this process the Earth's atmosphere becomes thicker with the influence substances such as gases

and the radiation coming from the sun is trapped, then the Earth becomes warmer. Green house effect is seen in global warming.

Carbon neutral can be described as a process of removing huge amount of carbon dioxide from the atmosphere in order to achieve zero carbon neutrality.It is also reffered to as carbon neutrality, and this can be achieved by actions of organizations, businesses and individuals .

Carbon neutral can be achieved in two ways;

: 1.) Maintaining a balance between carbon dioxide emissions and carbon removal by means of the process called carbon offsetting

2 ) the process of removal of carbon dioxide from the atmosphere in order to balance up emissions in another place.

Carbon positive is crucial to increase the positive influence of our daily activities on climate change and our resources.

while reduce the negative effect of our activities and business on evironment.

Therefore, the practice of making operations "carbon neutral" is a way to offset whatever damage is being done to the environment due to greenhouse gas emissions by purchasing credits from "carbon-positive" projects to balance out emissions is true because the harmful gasses that is been released to the atmosphere is balance up by the carbon neutral process hence the reduction in green house effect.

7 0
2 years ago
A person's blood type is determined by the presence and absence of specific antigens on the cell membrane. Which of these would
sukhopar [10]

Answer:

C - no antibodies

Explanation:

I dont think there is any blood type without antibodies

5 0
3 years ago
Astroturf is a durable artificial surface used to cover athletic fields. A soccer field 0.06214- mile-long by 253 ft wide is cov
love history [14]

Answer:

The weight of the Astroturf is 179,684.31 Newtons.

Explanation:

Length of a soccer field = 0.06214 mile = 328.0992 feet

(1 mile = 5280 feet)

Breadth of a soccer field  = 253 feet

Length of a Astroturf which soccer field is to be covered, l = 328.0992 feet

Breadth of a Astroturf which soccer field is to be covered ,b = 253 feet

Thickness of a Astroturf with which soccer field is to be covered = h

h = ½ inch = 0.5 inch = 0.041665 feet

(1 inches = 0.08333 feet)

Volume of the Astroturf ,V= l × b × h

V=328.0992 ft\times 253 ft\times 0.041665 ft=3,458.574 ft^3

Mass of the Astroturf = m

Density of the Astroturf = d = 187 oz/ft^3

d=\frac{m}{V}

m=d\times V= 187 oz/ft^3\times 3,458.574 ft^3=646,753.35 oz

1 oz = 0.0283495 kg

m=646,743.35 oz=646,743.35\times 0.0283495 kg=18,335.13 kg

Weight of the Astroturf = W

W = mg

=W=18,335.13 kg\times 9.8 m/s^2=179,684.31 N

The weight of the Astroturf is 179,684.31 Newtons.

8 0
3 years ago
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