A neutral atom of beryllium (Be) has an average mass of 9 amu and 4 electrons. How many neutrons does it have?

13
5
9
4

Answers

Answer 1

Answer:

It has 5 neutrons

Explanation:

The fact that it is a neutral atom tells us that the number of electrons and protons is the same:

The problem tells us there are 4 electrons, thus there are 4 protons.

The average mass of an atom is the sum of the number of protons and the number of neutrons:

Mass = # Protons + # Neutrons

With the above information in mind we can calculate the number of neutrons:

9 amu = 4 Protons + # Neutrons# Neurons = 5 Neutrons

Related Questions

Help me please:(:(:( with my bellwork
for brainiest

Answers

Answer:

Elements are made of only one kind of atom

Compounds are made of 2 or more elements chemically bonded together

Explanation:

Its right there????

Susan is investigating physical changes. To do this, she places some ice into a large bowl and seals it with a lid. She leaves the bowl on the counter for several hours until all of the ice has melted. Using a balance, Susan determines that the mass of both the water and the ice are equal. Why is the mass of the ice and the water the same? (SC.8.P.9.1)

Answers

Answer:

No mass loss

Explanation:

The mass of ice and the water in the different state are equal because the same of quantity of matter is present in both state of matter of matter.

In essence, the mass of the physical change process is conserved. When mass is conserved, matter is neither created nor destroyed but can be changed from one form to the other. This is in compliance with the law of conservation of matter. So, no mass was lost in the physical change process and the mass will remain the same.

1. All ___matter______ is made of atoms that cannot be ______________________ or ____________________. 2. All _______________ of a given __________________ are ___________________ in mass and __________________.

Answers

Answer:

All the matter that is made of atoms that cannot be broken or beaten into thin sheet .2All matters of a given book are in mass and mixture

which of these is a characteristic
of index fossils

Answers

Answer: A index fossil is any animal or plant preserved in the rock record of the earth that is characteristic of a particular span of geologic time or environment. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time.

Explanation:

What is the molar mass of B,(Croa)g?
a. 186 g/mol
b. 369 g/mol
C. 232 g/mol
d. 250 g/mol

Answers

I think the answer is C

What energy is formed when you put your hands together and rub them up and down rapidly

Answers

Your answer should be heat energy!

Answer:

When you rub your hands together thats mechanical energy. Once you hands warm up its heat energy.

Someone please help will mark as brainliest

Answers

1. solute is the substance that is being dissolve,while solvent is dissolving medium

2.saturated is solution that contain maximum amount of solut that capable of being dissolve and supersaturated is solution that contain less amount or medium of solut that capable being dissolve : example vinger

3. is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2 H2, and two molecules of water would be written 2 H2O . yes it's can be change only in caseWhen you balance an equation you can only change the coefficients

balancing equations help!!

Answers

1) N2+3H2–> 2NH3
2) 2KClO3–> 2KCl+3O2
3) 2NaCl+F2–> 2NaF+Cl2
4)Pb(OH)2+ 2HCl—> 2H2O+PbCl2
5) 2AlBr3+ 3K2SO4–> 6KBr+Al2(SO4)3
6) is already balanced

If you have any questions just let me know :)

Which of the following is a characteristic of covalent compounds?

Answers

they have bonds where electrons are shared between atoms.lower melting points and electrical conductivity compared to ionic compounds.

A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over
the next few minutes?
O Molecules in both the metal and the surrounding air will start moving at lower speeds.
O Molecules in both the metal and the surrounding air will start moving at higher speeds.
O The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
O The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

Answers

Answer:

It would be the third answer.

Explanation:

This is because over the next few minutes, the heat would radiate away from the atoms in the metal plate and the atoms around the plate would absorb this radiation.

Compared to ionic compounds, molecular compounds generally have

A. good conductivity.
B. greater densities.
C. more chemical bonds.
D. a low boiling point.

Answers

D.A low boiling point

Compared to ionic compounds, molecular compounds generally have a low boiling point and the correct option is option D.

What are Molecular compounds?

Molecular compounds are held together by covalent bonds. They are also called covalent compounds.

Covalent bonds are responsible for many of the properties of covalent compounds. Covalent compounds have relatively low boiling points, cannot conduct electricity, and may not dissolve in water.

Unlike ionic compounds, covalent compounds do not have freely moving electrons, so they cannot conduct electricity.

The individual molecules of covalent compounds are more easily separated than the ions in a crystal, so most covalent compounds have relatively low boiling points.

Therefore, compared to ionic compounds, molecular compounds generally have a low boiling point and the correct option is option D.

Learn more about Molecular compounds, here:

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what is formula for Bromine?

Answers

Br2

I looked it up and it said that Bromine's formula is Br2

Answer:Br2

Explanation:

What are two reasons that someone would want to become a scientist?
1 point
Your answer

Answers

Two reason someone would want to become a scientist to make exciting discoveries and discovered new life on our planet. Also you could solve huge problems that somebody else couldn’t solved. This is why somebody would want to be a scientist.

hhhhhhhhhheeelp !!! give 20 pintos

Answers

Answer:

you can run out of money the supplier could run out or they could stop making the renewable.

Explanation:

What is the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper?
Chemistry class I NEED HELP FAST

Answers

Answer:

the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper is it will help you get the right answer

Explanation:

True or false
Equal forces acting on one object in opposite directions are called balanced forces

Answers

Answer:

True

Explanation:

Forces, equal in magnitude and opposite in direction, and cancel each other out are called Balanced Forces.

Balanced Forces DO NOT cause any change in the velocity of the object, but the Object may correspond to a change in shape or size.

Example :

Blasting a balloon by compressing it tightly with both hands, roughly with an equal force, is a practical example of Balanced Forces. In this case, the balloon before the burst stays at a state of rest and same after the burst. But the burst or the compression, causes a change in the shape of the balloon.

how many dots would a dot diagram for selenium, one of the group 16 elements, have?

Answers

Answer:

Because selenium is in the 16th column on the periodic chart, it has 6 valence electrons. Thus, the Lewis structure (or electron dot structure) for selenium has 6 dots around it.

It will look similar to this without the underscores:

__.

. Se:

_. .

Explanation:

The Lewis structure (or electron dot structure) for selenium has 6 dots around it.

What is an electron dot structure?

Electron dot diagrams are diagrams in which the valence electrons of an atom are shown as dots distributed around the element's symbol.

Selenium is in the 16th column on the periodic chart, it has 6 valence electrons. Thus, the Lewis structure (or electron dot structure) for selenium has 6 dots around it.

Learn more about electron dot structure here:

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Form a bond: Each electron has a charge of 1–, and each proton has a charge of 1+. You can calculate the charge of an atom by subtracting the number of electrons from the number of protons. Move an electron from the sodium to the chlorine atom.

1. Sodium has a charge of 1+ and chlorine has a charge of 1-

2. Chlorine has a charge of 1+ and sodium has a charge of 1-

3. Both atoms have a charge of 1+

4. Both atoms have a charge of 1-

Answers

Answer:

1. Sodium has a charge of 1+ and chlorine has a charge of 1-

Explanation:

Sodium has 11 protons and 11 electrons. If you remove one electrons we now have only 10 electrons.

Hence; number of protons - number of electrons = 11 - 10 = +1

Sodium has a charge of +1

Chlorine has 17 electrons and 17 protons. if it gains 1 electron then it now has 18 electrons.

Hence; number of protons - number of electrons = 17 - 18 = -1

Chlorine has a charge of -1

is combustion an example of the law of conservation of matter and why?

Answers

Answer:

Explanation:

The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. For example, when wood burns, the mass of the soot, ashes, and gases, equals the original mass of the charcoal and the oxygen when it first reacted.

FOR 35 POINTS & A BRAINIST*
1.) For an atom of sulfur, there are
A.) two electron shells with 6 valence electrons
B.) three electron shells with 6 valence electrons
C.) four electron shells with 6 valence electrons
D.) five electron shells with 6 valence electrons

2.) Which atom has four electron shells with 7 valence electrons?
A.) F
B.) CI
C.) Br
D.) I

3.) Which atom has three electron shells with 8 electrons in its outermost orbit?
A.) He
B.) Ne
C.) Ar
D.) Kr

4.) Which method should be used to draw electrons that are involved in a collision during a chemical reaction?
A.) Bohr's model
B.) Lewis dot model
C.) Addition model
D.) Subtraction model

Answers

1.) B

2.) C

3.) C

4.) B

I genuinely double checked that these were right! I hope it helps!!

HELPPPPPPPPPPPPPPPPPPP

Answers

Answer:

not sure about the first one, but i know SDS provides information about the last 3.

Explanation:

Does anyone know how to determine if a reaction is a redox or not?
2Ca+O2→2CaO2 is the reaction. I've already made it a balanced equation, I just need to determine if its a redox or not.
Thank you!

Answers

The reaction is included in a redox reaction

Further explanation:

Given

Reaction

2 Ca + O₂ → 2 CaO

Required

a redox reaction

Solution

Redox reactions are reactions where there is a change in oxidation number

Oxidation is an increase/increase in oxidation number, while reduction is a decrease/decrease in oxidation number.

Reducing agents are substances that experience oxidation  and oxidizing agent are substances that experience reduction

in the above reaction is included in a redox reaction because there is a change in oxidation number

Ca⇒Ca²⁺+ 2e⁻(for balanced equation : 2Ca⇒2Ca²⁺+4e⁻)

Oxidation ( 0 to +2)

O₂+2e⁻⇒O²⁻(for balanced equation : O₂+4e⁻⇒2O²⁻)

Reduction (0 to -2)

Condensation point and freezing point of argon in KELVIN.

Answers

Answer:

Condensation: 423.3 K

Freezing: 83.96 K

(this is all i could figure out :) hope it helps)

Can someone define these for me

Answers

Answer:

These are all in order....

Explanation:

- closed system usually absorbs thermal energy from its surroundings, which is heat transfer into the system

- a solute is a substance dissolved in another substance, known as a solvent

- A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid

- a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent)

- a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy

- a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.

- Half-life is the time required for a quantity to reduce to half of its initial value

- the determination of the age or date of organic matter from the relative proportions of the carbon isotopes carbon-12 and carbon-14 that it contains. The ratio between them changes as radioactive carbon-14 decays and is not replaced by exchange with the atmosphere.

- any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so quantity can neither be added nor be removed

Using the model of the periodic table, which element pictured represents an unreactive gas?

Answers

Answer:

2

Explanation:

Nobel gasses are not reactive and are the far right group on the periodic table.  This is because they have a full valence electron shell which is the most stable electron configuration.  Most reactions occur in order for an atom to fill its valence shell and since they already have a full valence shell there is no reason for them to react.

A boundary between air masses that don't move possibly causing rain for several days.

Answers

Answer:

A Front

Explanation:

A Front is a boundary between two air masses of different density, moisture, or temperature

two negative charges are placed near each other. what happens between the charges

Answers

Answer:

repulsion

Explanation:

Answer:

Explanation:

In contrast to the attractive force between two objects with opposite charges, two objects that are of like charge will repel each other. ... Similarly, a negatively charged object will exert a repulsive force upon a second negatively charged object. Objects with like charge repel each other.

What is the name of the family with an oxidation number of +2?
a. Halogens
b. Alkali Earth Metals
c. Noble Gasses
d. Transition Metals

Answers

Answer:

Alkali Earth Metals

Explanation:

The oxidation number is equal to the charge which is determined by the valence electrons. Alkali Earth Metals all have 2 valence electrons and, therefore, an oxidation number of 2.

Answer:

+2alkaline earth metal and +1 oxidation number is alkali metal

Explanation:

alkali is Arabic word means ash

Help please When you are measuring your pulse (heart beats per minute) what system are you monitoring?
A. Digestive
B. Respiratory
C. Circulatory
D. Integumentary (skin)

Answers

The answer is C.Circulatory because its made up of blood vessels that carry blood away from and towards the HEART

Show your work with good use of units, rounding, and significant figures. [Hint: it is good practice to show the value of your answer before you round off to the final answer with the correct significant figures!]

(8 points) How much heat is required to convert 10.00 g of ice at –20.00°C to water at 25°C. The specific heat of ice is 2.09J/g°C; the specific heat of water is 4.182 J/g°C; the heat of fusion is 333.0 J/g.

Group of answer choices

Answers

Heat required : 4.8 kJ

Further explanation

The heat to change the phase can be formulated :

Q = mLf (melting/freezing)

Q = mLv (vaporization/condensation)

Lf=latent heat of fusion

Lv=latent heat of vaporization

The heat needed to raise the temperature

Q = m . c . Δt

1. heat to raise temperature from -20 °C to 0 °C

[tex]\tt Q=10\times 2.09\times (0-(-20)=418~J[/tex]

2. phase change(ice to water)

[tex]\tt Q=10\times 333=3330~J[/tex]

3. heat to raise temperature from 0 °C to 25 °C

[tex]\tt Q=10\times 4.18\times (25-0)=1045~J[/tex]

[tex]\tt Q~tot=418+3330+1045=4793~J\rightarrow rounding~and~2~sig~figs=4.8~kJ[/tex]

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