An isotope of lead can be represented by the following symbol ²⁰⁷ 82 PB. From this symbol, it can be deduced that one atom of the isotope has: A) 82 neutrons B) 82 protons C) 125 protons D) 207 protons

Answers

Answer 1

Answer:

B) 82 protons

Explanation:

The number of protons for an element never change. 82 Is the atomic number for Pb which is how many protons it has. An isotope means it has more neutrons.


Related Questions

What statement describes the cause for sibling rivalry between both brothers? The older son shared his fears about providing financial support for the family after graduating. The sons challenged each other by competing for the highest grade point average that year. The younger son expressed feelings about his parents showing favoritism to his older sibling. The sons disagreed over the handling of family tasks once the younger son heads off to college

Answers

Answer:

c

Explanation:

you took the test on edge

The statement describes the cause for sibling rivalry between both brothers is The younger son expressed feelings about his parents showing favoritism to his older sibling. Hence , Option (C) is correct.

What is Sibling rivalry ?

Sibling rivalry is the jealousy, competition and fighting between brothers and sisters.

It is a concern for almost all parents of two or more kids.

Problems often start right after the birth of the second child.

Sibling rivalry usually continues throughout childhood and can be very frustrating and stressful to parents.

Therefore, The statement describes the cause for sibling rivalry between both brothers is The younger son expressed feelings about his parents showing favoritism to his older sibling. Hence , Option (C) is correct.

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Which of the following elements does not lose an electron easily? NA F MG AL

Answers

Answer:

F

EXPLANATION

Among the given elements fluorine(F)can not lose electrons easily because of its high electron affinity, high nuclear charge and high electronegativity.

Answer:

F

Explanation:

it won't lose electron , rather it would gain electron to complete its octate......

Electronic Configuration of F = 2,7

So F will gain 1 electron ....

answer the question briefly: How can atom collapse and why are atoms stable?

Answers

The nuclei of atoms become unstable when the repelling forces of the protons cannot be balanced by the number of neutrons in the nucleus. It then re-arranges itself randomly to a more stable configuration by emitting any of a series of particles. During radioactive decay, an atom does not collapse.

Since an atom is mostly empty space - that is it’s nucleus is relatively distant from the electron shells so, in the presence of extreme forces such as gravity inthe collapse of a large star, the inward pressures on the atom overcome the natural balance of the atomic structure and the ‘empty space’ disappears as nuclei are mashed together by the intense pressures and a neutron star is formed. Under even more external pressure, even the neutron star can collapse to form a black hole.

Name a Solid, Liquid, and a Gas. Solid: Liquid: Gas:

Answers

Answer:

Gas - Steam

Solid - Rock

Liquid - Juice

Answer:

Solid: Ice

Liquid: Water

Gas: Steam or Water vapor

Explanation:

This is a common example to answer your question. Some other examples are:

-most metals(ex: iron, tin, copper, gold) These are solids

-milk, juice, hot chocalate, any soda drink These are liquids

-hydrogen, helium, carbon dioxide, oxygen These are gases

Hope this helps!

Ammonia is produced when a mixture of of ammonium chloride and substance C is heated. What is substance X?

Answers

The substance X is NaOH

An atom of an element is shown by the model. A gray circle is surrounded by 4 concentric circles. The innermost circle has gray dots at the north and south positions; the second ring has 8 equally spaced dots, aligning with the inner ring at north and south; the third ring has 14 dots, equally spaced, aligned with the other rings at north and south; the outer ring has dots at north and south. How is this model useful? It shows how electrons are distributed in the shells of an iron atom. It shows how electrons are distributed in the shells of a cobalt atom. It shows how orbitals are distributed in the shells of an iron atom. It shows how orbitals are distributed in the shells of a cobalt atom.

Answers

The correct answer is A. It shows how electrons are distributed in the shells of an iron atom.

Explanation:

In the model described, the circles represent the orbitals or shells of the atom, while the dots represent the distribution of electrons (negatively charged sub-particles). Additionally, the description shows the general electronic configuration of this atom is 2, 8, 14, 2, which means in the first orbital there are two electrons, in the second there are eight electrons, in the third, there are fourteenth electrons and in the fifth orbital there are two electrons. This electronic configuration occurs in the atoms of iron. Also, this differs from Cobalt because in cobalt the third orbital has 15 electrons. Thus, the model "shows how electrons are distributed in the shells of an iron atom".

Answer:

a. it shows how electrons are distributed in the shells of an iron atom

Explanation:

edge 2021

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suppose a 22.092 g sample of 1 1 mixture of acetylferrocene and ferrocene was sepeerated by column chromatography and the recovered fractions weighed 9.017 g acetylferrocene and 8.075 g ferrocene what was the eprcent recovery of acetyl ferrocene

Answers

Answer:

Percentage recovery of acetylferrocene = 81.6%

Explanation:

Mass of the sample mixture = 22.092 g

Ratio of mixture of acetylferrocene and ferrocene = 1 : 1

This means that the sample conatains equal amounts of acetylferrocene and ferrocene.

Therefore the mass of each sample in the mixture = 22.092 g / 2 = 11.046 g

Mass of acetylferrocene recovered = 9.017 g

Percentage recovery of acetylferrocene = (mass of recovered/ mass in sample) * 100%

Percentage recovery of acetylferrocene = (9.017 g / 11.046 g) *100%

Percentage recovery of acetylferrocene = 81.6%

The cell potential of an electrochemical cell is positive. What does that tell
you about the redox reaction?
A. The reduction part of the reaction occurs at the anode.
B. The oxidation part of the reaction occurs at the cathode.
C. The reaction is spontaneous.
O D. The reaction is nonspontaneous.

Answers

Answer:

A. The reduction part of the reaction occurs at the anode

Answer:

A

Explanation:

Label the following as either an Element, Compound, or Mixture.

Answers

Answer:

27. Element (Because it contains all same atoms)

28. Compound (It contains atoms held together through chemical bonds)

29. Element (it contains all same atoms)

33. Mixture (It contains different atoms but they are not held together through chemical means)

34. Compound (Different atoms held together through chemical means)

35. Mixture (Mixture of elements and compounds)

30. Element (it contains all same atoms)

31. Mixture (Mixture of elements and compounds)

32. Element (Contain all same atoms although held together through chemical means they are not compounds)

Energy from a reaction was determined to be 3870 J using a water calorimeter, when burning 9.00 grams of H­2. What is the total enthalpy of the reaction?

Answers

Answer:

860 J / mol

Explanation:

Enthalpy = Energy / no. of moles

no. of moles = mass / molar mass

Take the atomic mass of H = 1.0,

molar mass of H2 = 1.0 x 2

= 2.0

no. of moles of H2 = 9.00/2

= 4.5 mol

Hence,

Enthalpy = 3870 / 4.5

=860 J / mol

D Serum Levels Of 4 Mcg/mL, Calculate The Dose, In Milligrams, For A 120-lb Patient That May Be Expected To Result In A Blood Serum Gentamicin Level Of 4.5 Mcg/mL. This problem has been solved! See the answer If the administration of gentamicin at a dose of 1.75 mg/kg is determined to result in peak blood serum levels of 4 mcg/mL, calculate the dose, in milligrams, for a 120-lb patient that may be expected to result in a blood serum gentamicin level of 4.5 mcg/mL.

Answers

Answer:

The patient requires a dose of 107.2 mg of gentamicin

Explanation:

A dosage of 1.75 mg per Kilogram body weight results in blood serum levels of 4.5 mcg/mL

This means that; 1.75 mg/ kg = 4.0 mcg/mL

Therefore, dosage of gentamicin in  mg/kg that will result in 4.5 mcg/mL blood serum level = (1.75 mg/Kg * 4.5 mcg/mL) / 4.0 mcg/mL

Dosageof gentamicin = 1.97 mg/Kg

1-lb = 0.453592 Kg

Weight of 120-lb patient in Kg = 120 * 0.453592 = 54.43 Kg

Dose in mg required by patient = 1.97 mg/Kg * 54.43 Kg = 107.2 mg

Therefore, the 120-lb patient requires a dose of 107.2 mg of gentamicin to result in a blood serum level of 4.5 mcg/mL

Which statement describes an electron?

Answers

Answer:

The statement that describes an electron is "It has a negative charge and is located in orbitals around the nucleus." Electrons are the smallest of the three particles that make up atoms

Explanation:

Electrons are found in shells or orbitals that surround the nucleus of an atom

Electrons are the sub-atomic particles that carry a negative charge over them. In the atom, the electrons are found in the orbitals or the shells around the nucleus. Thus, option D is correct.

What are electrons?

Electrons are the smallest sub-atomic particle that has been known to carry a negative charge and are found in the orbitals of the atom. The charge carried by an electron is 1.602 x 10⁻¹⁹ coulomb and is small than the proton and neutron.

They revolve around the nucleus in their orbits and exhibit the properties of waves and matter. The number of electrons and protons are the same in a neutral atom which makes the atomic number.

Therefore, the electrons have been known to carry a negative charge that revolves in orbit around the nucleus.

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Your question is incomplete, but most probably your full question was, Which statement describes an electron?

It has a positive charge and is located in the nucleus. It has a positive charge and is located in orbitals around the nucleus. It has a negative charge and is located in the nucleus. It has a negative charge and is located in orbitals around the nucleus

12. Classify the following as conduction, convection or radiation. a. A steel mug kept near a stove becomes hot after some time. b. The metal handlebars of a bicycle are colder than plastic hand grips. c. Some people get sunburn when they go out in the sun for a long time. d. The paper kept above a candle flame starts burning after some time.

Answers

A - convection

B - conduction

C - radiation

D - convection

Which of the following observations indicates that atoms of all elements contain small, negatively charged particles? Alpha particles are repelled by cathode rays of elements. Cathode rays are deflected towards a positively charged rod. A particular frequency of light is produced by a gas in an excited state. Certain areas of the atom called orbitals contain all the charged particles.

Answers

Answer:

The correct option is;

Cathode rays are deflected towards a positively charged rod

Explanation:

Cathode rays are  beam of electrons emitted from the cathode in a vacuum tube and moving towards the anode, due to the difference in the voltage between the electrodes

The discovery of the electrons was through the proof by Thomson that cathode rays were a negatively charged, previously unknown particle, which was to become known as the electron.

Answer:

Cathode rays are deflected towards a positively charged rod

Explanation:

i took the exam this is correct

1. The atomic symbol of aluminum is written as 2713Al. What information do you get from it?

Answers

Answer:

its mass number and atomic number

Explanation:

atlmic number(subscript)=13

mass number(superscript)=27

To dissolve in water, aluminum (AI) should form a compound with
oxide (O2-).
sulfide (S2-).
nitrate (NO,-).
phosphate (POP).

Answers

Answer:

Explanation:

Nitrate of most of the elements are water soluble . Aluminium nitrate is also one of them . Aluminium nitrate is easily dissolved in water . It forms hydrated salt whose formula is as follows

Al( NO₃ )₃ . 9H₂O

It is a white crystalline salt . It is also soluble in alcohol.

what happens when ca no3 2 is heating it gives CaO ,NO2 and 02

Answers

Answer:

balanced equation:

2Ca(NO3)2 (aq)-----> 2CaO (s) + 4NO2 (g) + O2 (g)

So heating 2 moles of Ca(NO3)2 gives 2 moles of CaO, 4 moles of NO2 and 1 mole of O2. This is a heat decomposition reaction. It gives a white precipitate (CaO), and brown pungent gas (NO2).

Answer:

The balanced equation of the reaction is below.

Explanation:

2Ca(NO3)2 -----> 2CaO + 4NO2 + O2.

In an endothermic reaction, a drop in temperature would be observed. TRUE FALSE

Answers

Explanation:

If the reaction is endothermic as written, an increase in temperature will cause the forward reaction to occur

The steady state vital to life is possible because:________
a. the cell cannot convert energy from one form to another.
b. all cells are autotrophic.
c. all reactions are exothermic.
d. the cell continually takes up energy from the environment.
e. all reactions are at equilibrium.

Answers

Answer: The correct answer is e) all reactions are at equilibrium.

Explanation: In order for cellular vitality to develop, it is necessary for it to be in energetic balance with the environment, that is, to give and receive energy with the environment that surrounds it through endothermic or exothermic reactions. That is why the development of life is considered a system that constantly exchanges with the environment. In turn, that the cell unit maintains a balance with the environment causes homeostasis to occur among the whole organism.

write chemical equation for the following decomposition reactions. Aluminum oxide(s) decomposes when electricity is passed through it.

Answers

Answer:

2Al2O3 (l) ---> 4Al (l) + 3O2 (g)

Explanation:

The reaction is the electrolysis of aluminium oxide. It decomposes aluminium oxide (Al2O3) into aluminium metal (Al) and Oxygen (O2). In this process, aluminium oxide is molten (liquid state) so that ions can move to complete the electricity circuit.

Al2O3 (l) ---> Al (l) + O2 (g)

Balance the equation:

2Al2O3 (l) ---> 4Al (l) + 3O2 (g)

show bond formation in magnesium chloride​

Answers

mg has a 2 in its valence shell

it will become mgcl2

. . . .

: Cl -------- Mg ------ Cl :

. . . .

what particle determines the name of the element?

Answers

Answer:

The protons determine the name of an element and also atomic number because its the same as protons.

To make a table of elements, dmitri

Answers

The question is incomplete, the complete question is;

To make a table of the elements, dimitri Mendeleev sorted the elements according to their?

Answer:

Atomic weights

Explanation:

Dimitri Medeleeve is a Russian scientist who worked assiduously on the project of developing a system of classifying all the elements. His periodic table was filled with spaces as many atoms weren't yet discovered. 'Eka' prefix was used to name some elements whose properties closely resembled that of their predecessors in Mendeleev's system of classification.

The dependence of the atomic properties on the weight of the atom was the basis for Mendeleeves' original classification. According to Medeleeve, elements having similar chemical properties are also expected to have similar atomic weights and their atomic weights was found to increase regularly.

The Mendeleeve concept of periodic arrangement of elements is the closest precursor of the modern periodic table as it is used in chemistry. Mendeleev arranged the elements in order of increasing relative atomic mass .

What letter represents the enthalpy of reaction?

Answers

Answer:

Option D. T

Explanation:

Enthalpy change (ΔH) is simply the difference between the heat content of the product (Hp) and the heat content of the reactant (Hr). Mathematically, it is expressed as:

Enthalpy change (ΔH) = Heat of product (Hp) – heat of reactant (Hr)

ΔH = Hp – Hr

From the diagram given above, the difference between the heat content of product and the heat content of reactant is T.

Therefore, the enthalpy change of the reaction is T.

Question 7 of 25
What is an energy level?
A. The total energy possessed by all the electrons of an atom
B. The energy contained within the nucleus of an atom
C. The energy required to remove an electron from its nucleus
D. The energy possessed by an electron at a set distance from the
nucleus
SUBMIT

Answers

Answer:

d)the energy possessed by an electron at a set distance from the nucleus

To what temperature should 2.3L of a gas at 25degree Celsius be heated in order to expand its volume to 4 L under constant pressure

Answers

Answer:

518.52K

Explanation:

Charles law, which describes the direct relationship between the volume and the temperature of a gas when the pressure is constant, will be used for this question. The Charles law equation is:

V1/T1 = V2/T2

Where; V1 is the volume of the gas at an initial state (Litres)

T1 is the absolute temperature of the gas at an initial state (Kelvin)

V2 is the volume of the gas at a final state (Litres)

T2 is the absolute temperature of the gas at a final state (Kelvin)

According to the question, V1 = 2.3L, T1 = 25°C, V2 = 4L, T2 = ?

We need to convert the temperature to the absolute temperature unit in Kelvin (K) i.e.

T(K) = T(°C) + 273.15

T(K) = 25°C + 273.15

T1 (K) = 298.15K

To find for T2 in the equation, we make T2 the subject of the formula:

T2 = V2 × T1 / V1

T2 = 4 × 298.15 / 2.3

T2 = 1192.6/2.3

T2 = 518.52

Thus, the temperature must be heated to 518.52K in order to expand to a volume of 4L. This answer is in accordance to Charles law that the volume increases with increase in temperature and vice versa.

What mass of oxygen gas contains the same number of moles as 56g of sulphur? (Relative atomic mass: S = 32, O = 16) A) 0.56g B)5.6g C)56g D)560g

Answers

Answer:

The answer is option C

Explanation:

To calculate the mass of oxygen gas we must first find the number of moles of sulphur

Molar mass = number of moles (n) / mass

n = mass / Molar mass

From the question

Molar mass (M) of Sulphur = 32g/mol

mass = 56g

n( Sulphur) = 56/32 = 1.75mol

Since the moles of oxygen and sulphur are the same

M(O2) = 16 × 2 = 32g/mol

Mass of oxygen = molar mass × moles

= 32 × 1.75

= 56g

Hope this helps you

PLEASE HELP ME

One method to produce nitrogen in the lab is to react ammonia with copper (II) oxide: NH3(g) + CuO(s) ---> Cu(s) + H2O(l) + N2(g). After using 40.0 grams of NH3, 15.5 grams of N2 are produced. What is the percent yield of nitrogen in the reaction?

Answers

Answer:47.05% is the percent yield of nitrogen in the reaction.

Explanation:

heoretical yield of nitrogen gas = x

Moles of ammonia =  

According to reaction,2 moles of ammonia gives 1 mol of nitrogen gas.

Then 2.3529 mol of ammonia will give:

of nitrogen gas

Mass of 1.1764 moles of nitrogen gas,x = 1.1764 mol × 28 g/mol=32.94 g

Experiential yield of nitrogen gas = 15.5 g

Percentage yield:

hope that help

47.05% is the percent yield of nitrogen in the reaction.

calculate the mass of sodium sulphate required to prepare its 20%of solution in 100 g ofwater​

Answers

Answer:

25 g

Explanation:

Mass percent implies the mass of solute dissolved in a solution

Mass percent = mass of solute/mass of solute + mass of solvent × 100/1

Since mass percent concentration= 20%

Mass of solvent = 100g

Let mass of solute = x

Hence;

20 = x/x +100 ×100/1

20/100= x/x + 100

0.2 = x/x + 100

0.2(x + 100) = x

0.2x + 20 = x

20 = x - 0.2x

20 = 0.8x

x= 20/0.8

x= 25 g

how to make a salt by neutralization reaction

Answers

Answer:

Acid+Base=Salt+water

This is the formula of neutralization reaction.

According to this formula you can make salts by reacting an acid with a base.

Hope this helps ❤❤❤.

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