Am element has 18 electrons ,20 neutrons and a charge of -2.what is the mass number?..a.38 b.40 c.32 d.39​

Answers

Answer 1

Answer:

Surely you must have a Periodic Table beside you....?

a=38

Explanation:

You gots Z=18, the atomic number, where Z is the number of nuclear protons. The number of protons defines the element....and thus we got calcium....

....and with 20 neutrons we got the 38Ca isotope....the which is rather short-lived...


Related Questions

Please help!!! Question 1 to 8

Answers

Answer:

1) C - 30

2) A - MgO

3) C - 3Cu + N2 + 3H2O

4) C - 100

Explanation:

Who developed the gas law that relates pressure and temperature?

Answers

Explanation:

physicist Robert Boyle

Answer: Boyle

Explanation: Educere Answer

Which of the following is a result of increasing the temperature of a system that includes a reaction in the forward direction that is exothermic?
a) The equilibrium constant decreases.
b) The concentrations of the products increase.
c) The equilibrium constant increases.
d) The concentrations of the reactants decrease.

Answers

Answer:

I believe the answer your looking for is out of A or B

Explanation:

Option B because if the heat increases its essentially causing the concentration to increase by replacing the weak bonds with stronger ones

In increasing the temperature of a system that includes a reaction in the forward direction that is exothermic, the concentration rises as weak bonds are replaced by stronger ones.

What is the temperature of a system?

The average kinetic energy of the atoms or molecules in a system is measured by temperature. No heat is transmitted between two objects in thermal equilibrium, according to the zeroth law of thermodynamics.

In conclusion, as the temperature of the system rises, the concentration rises as weak bonds are replaced by stronger ones.

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Write the chemical symbols for three different atoms or atomic cations with 11 electrons.

Answers

Three ways to represent atoms or atomic cations with 11 electrons include :

[tex] {Mg}^{ + } \: {Al}^{2 + } \: {Si}^{3 + } [/tex]

Mg = magnesium has 12 electrons in its neutral state, when it loses one electron to attain stability, it's election becomes 11.

Al = Aluminum has 13 electrons in its neutral state, when it donates 2 electron to attain stability, it becomes (13 - 2). = 11

Si = Silicon has 14 electrons on it's neutral state, when it loses 3 electrons to attain stability, we have (14 - 3) = 11

Hence,

[tex]{Mg}^{ + } \: {Al}^{2 + } \: {Si}^{3 + } [/tex]

are atomic cations with 11 electrons.

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How would life be different without penicillin

Answers

Answer:

Without new antibiotics, common infections and minor injuries could become life-threatening and major surgeries and chemotherapy impossible because the treatments we have been using for years are no longer effective.

if 10 moles of A and 7.5 moles of B are taken in a flask, identify the value of moles of A4B3 produced in a reaction.​

Answers

The number of moles of A4B3 produced in a reaction is obtained  by stoichiometry.

The term stoichiometry refers to mass-mole relationship. The first step in solving this problem is by writing the correct reaction equation as follows;

4A + 3B -------> A4B3

If 4 moles of A yields 1 mole of A4B3

10 moles of A yields 10 * 1/4 = 2.5 moles of A4B3

Therefore, 2.5 moles of A4B3  is produced.

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In a fission reaction a 235U nucleus captures a neutron. This results in the products 141Ba and 92Kr along with how many neutrons?
A. 1.
B. 2.
C. 3.
D. 5.

Answers

B 2 neutrons. total initial mass is 235 when it fissions, the total mass need to be conserved. hence 141+92=233 it shows that there are 2 neutrons (1 mass each) as another product

Evolution means..... exchanges gradual development transcription differentiation​

Answers

Explanation:

Evolution means Gradual Development. It is a procedure in the gradual development in which species of different animal's, plants etc... leisurely started to change some of their activities or elements and it changes only due to some situations it changes over many generations also.

Answer:

mark me as a brainlist answer i hope it will help you

Explanation:

Evolution means Gradual Development. It is a procedure in the gradual development in which species of different animal's, plants etc... leisurely started to change some of their activities or elements and it changes only due to some situations it changes over many generations also.

The density of Silver is 10.5 g/mL. How much mass would be present given a silver cube
with a volume of 25.0 mL?


PLEASE HELP ASAP

Answers

Answer:

m=dxv

= 10.5 x 965 = 10132.5 rounded off to 10100 g

Explanation:

is time a fundamental quantities or units?

Answers

Answer: Its fundamental quantities

The SI is on the seven SI base units for seven base quantities.

pls mark brainliest

The lines of latitude are measured
from a line at the center of the Earth
called the


Answers

Answer:

parallels

Explanation:

hope it may help you

10 advantages of atomic absorption spectrometer over flame photometer​

Answers

Answer:

(1) It does not suffer from spectral interference, which occurs in flame emission spectroscopy.

(2) By atomic absorption technique, traces of one element can easily be determined in presence of high concentration of other elements.

The technique makes use of the atomic absorption spectrum of a sample in order to assess the concentration of specific analytes within it. It requires standards with known analyte content to establish the relation between the measured absorbance and the analyte concentration and relies therefore on the Beer–Lambert law.

The mass of all the water on earth is 1.4 x 1024 grams. How do you think
someone was able to measure that number?

Answers

The numbers for the measure are 183

How can the Swartz process be modified to work for bacteria? Explain.​

Answers

Answer:

https://swartzbiotechnologylab.sites.stanford.edu/research

Explanation:

Alkyl chlorides and alkyl bromides are typically transformed into alkyl fluorides in the organic reaction known as the Swarts Reaction.

Swartz reaction?

Frederick Jean Edmond Swarts first reported this procedure in 1892. Heating the alkyl chloride or alkyl bromide in the presence of heavy metal fluorides like AGF, Hg2F2, CoF2, or SbF3 causes this reaction.

Swartz process can be used to modify work for bacteria. Bacterial biofilms are collections of microorganisms where the cells are immersed in an extracellular polymeric matrix that the bacteria have self-produced.

In contrast to planktonic bacteria, which are in a state of free movement in a bulk solution, this situation is very different.

Applications:

In this process, alkyl fluorides are created.Fluorinated aliphatic organic molecules, or Freons, are produced via a different variation of the same process.Anhydrous hydrogen fluoride is fluorinated to produce Freons in the presence of antimony salts, which exhibit the oxidation states +3 and +5.

Therefore, Alkyl chlorides and alkyl bromides are typically transformed into alkyl fluorides in the organic reaction known as the Swarts Reaction.

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Equal masses of five unknown non-electrolytes are dissolved in water and the boiling point elevations are measured. Rank the following non-electrolytes from highest to lowest molar mass.
A. Boiling point of D (aq) = 103.2 degree C
B. Boiling point of A (aq) = 102.4 degree C
C. Boiling point of E (aq) = 101.3 degree C
D. Boiling point of B (aq) = 101.9 degree C
E. Boiling point of C (aq) = 100.5 degree C

Answers

Not sure but good luck

The allele for dimples is dominant and the allele for no dimples is recessive. If two parents that are heterozygous for dimples produce a child, what are the chances the child will have dimples? A. 25% B. 50% C. 75% D. 100%

Answers

The chances the child will have dimples is 50%. Hence The correct option is (B).

What is Heredity ?

Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents.

There is a 50% chance that the child does not obtain the allele needed for dimples (dd), and a 50% chance that the child is heterozygous (Dd). Because dimples is an autosomal dominant trait, heterozygosity will express dimples, leading to a 50% chance that the child will have dimples.

Therefore, The chances the child will have dimples is 50%. Hence The correct option is (B).

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0.5 mole of Na2SO4 x 10 H2O consists of what​

Answers

Answer:

» It contains two atoms of sodium sulphate

» It contains 10 molecules of water.

How does the volume occupied by a cubic centimeter (cm3) compare with the volume occupied by a milliliter

Answers

Answer:

One cubic centimeter is equal to one milliliter. Cubic centimeter is used interchangeably with millimeter. Centimeter belongs in the CGS unit system (centimeter-gram-second system) while liter belongs in the SI (Système International d'Unités)  unit system. These two are equal.

Explanation:

How many square centimeters are in an area of 5.90 inch^2 ?

Answers

Answer:

38.0644 cm^2

Explanation:

5.90 ×6.451   cm^2

The atomic size of atoms ________. A) increases going across a period B) decreases going down within a group C) increases going down within a group D) does not change going down within a group

Answers

Answer: my answer is A) increases going across a period

Explanation: because of it nuclear charge as it increases going across a period

HOPE THIS HELPSSSSS!!

halogens can react with metals by accepting a/an____ from a metal atom and forming an ionic compound

Answers

halogen can react with metals by accepting an electron from metal atom forming ionic compound ( metal forms + ion, halogen forms - negative halide ion)

3(b) The balloon did not burst when it is pressed onto 100 nails because
1. the nails are not sharp

2.the surface area of 100 nails produce high pressure on the balloon
3. the larger surface area of 100 nails produce low pressure on the balloon



3(c) To reduce pressure on the contact surface, we must apply force onto the .................... surface area.
1.largest
2.smallest
3. Any size of

Answers

3(b) 3 is correct the larger surface area of 100 nails produce low pressure on the balloon

3(c) to reduce pressure force must be applied to the largest surface area (1)

pressure = Force/Area

PLEASE SOLVE THIS QUESTION.
VERY MUCH IMPORTANT ​

Answers

Answer:

[tex]thank \: you[/tex]

what is the source of energy that is absorbed by the electrons to move from the ground state to excited state?

Answers

Answer:

I think an atom changes from a ground state to an excited state by taking on energy from its surroundings in a process called absorption. The electron absorbs the energy and jumps to a higher energy level. In the reverse process, emission, the electron returns to the ground state by releasing the extra energy it absorbed.

I hope this help you!:)

Which species is the conjugate acid of the hemiacetal formed by reaction of benzaldehyde with methanol containing a trace of acid?

Answers

Answer:

Sulphuric acid is the on

Explanation:

think so

PLEASE ANSWER ASAP NEED ANSWER!!!!!!!!!!!!!! 75 POINTS

Which statement about pure substances and molecules is correct?

A. Pure substances cannot be molecules.

B. All molecules are pure substances.

C. Molecules cannot be pure substances.

D. All pure substances are molecules.

Answers

Answer:

D. All pure substances are molecules.

The correct statement about pure substances is; "All molecules are pure substances."

A pure substance contains exactly the same type of atoms. In a molecule, there can only be a particular combination of atoms.

For instance, a molecule of HCl can only contain chlorine and hydrogen atoms.

This means that every molecules are also pure substances.

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what will I benefit or what will I gain if I know the absorbance and emission of any substance?

Answers

You will gain more knowledge and it will be for your own good

The ideal gas constant R can be denoted as _______.
A. R = 9.315 (Pa × m3) / (mole × K)
B. R = 9.315 J / (mole × K)
C. R = 0.0821 (L × atm) / (mole × K)
D. All of the Above E. None of the Above

Answers

only C is correct

in the unit of J/(mole x K) and (Pa x m3)/ (mole x K) the value should be 8.314

What is the volume of 12.0 g of a liquid with a density of 1.37 g/mL?

Answers

Answer:

8.76 ml³

Explanation:

volume = mass ÷ density

Acrylonitrile and ethyl acetate have the same boiling point: 77.2ºC. In one to two sentences, explain what outcome you would expect if a mixture of these two substances were distilled (SHORT ANSWER)

Answers

Acrylonitrile and ethyl acetate will be collected together since they both have the same boiling point.

The method of distillation highly depends on the difference between the boiling points of the Acrylonitrile and ethyl acetate.

Since they have the same boiling point, the two substances turn into vapor at the same temperature and are collected simultaneously.

Hence separation is not achieved by distillation.

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Answer:

They would boil at the same rate. Basically meaning, that they would both be finished distilling at the same time.

Explanation:

This is what I put (this is for you to revise and it has not been graded yet DO NOT CHEAT with this answer just take in the info and revise it)

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