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3 years ago

What element has 2 electrons in its outermost energy level and is in the 2nd period on periodic table?

Chemistry

1 answer:

Olegator [25]3 years ago

4 0

Be-beryllium have 2 electrons and it is in the 2 nd period

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Plants need sunlight to make food during the process of:

Andrej [43]

the answer is photosynthesis

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3 years ago

The atoms of platinum and silver are identical (true or false)

koban [17]

Answer:

I think it's false but not sure

3 0

2 years ago

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How many neutrons and protons are there in the nuclei of the following atoms. a. Li-7 b. O-16 c. Th-232 d. Pu-239

ANEK [815]

Answer:

P = 3 , N = 4

P = 8 , N = 8

P = 90 , N = 142

P = 94 , N = 145

Explanation:

Mass number = Number of protons + Number of neutrons

Also,

Atomic number = Number of protons

Li - 7

Given, Mass number of Lithium = 7

For lithium, atomic number = 3

So,

Number of protons = 3

Number of neutrons = Mass number - Number of protons = 7 - 3 = 4

O - 16

Given, Mass number of oxygen = 16

For oxygen, atomic number = 8

So,

Number of protons = 8

Number of neutrons = Mass number - Number of protons = 16 - 8 = 8

Th - 232

Given, Mass number of Thorium = 232

For Thorium, atomic number = 90

So,

Number of protons = 90

Number of neutrons = Mass number - Number of protons = 232 - 90 = 142

Pu - 239

Given, Mass number of Plutonium = 239

For Plutonium, atomic number = 94

So,

Number of protons = 94

Number of neutrons = Mass number - Number of protons = 239 - 94 = 145

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3 years ago

What phases are most common at high temperatures

Nikitich [7]

Answer:

Liquids and gases.

For most substances, when heated to a high enough temperature, the molecules begin moving faster which results in its liquid or gas state.

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3 years ago

In an investigation with density, Marcia’s teacher measures the mass and volume of 10 different samples of a substance. The samp

valina [46]

Answer:

Mass

Step-by-step explanation:

Usually, you plot the independent variable along the horizontal (x) axis and the dependent variable along the vertical (y) axis.

Marcia's teacher plotted the mass of the sample along the x-axis and volume along the y-axis.

The mass is the independent variable, because that is what the teacher varied.

The volume is the dependent variable, because it depends on the mass.

Sample number is wrong, because it is not a variable.

Substance is wrong, because all samples consist of the same substance.

Density is wrong, because it is constant. It is the slope of the graph.

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3 years ago

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