Which two letters represent elements that are in the same period

Answers

Answer 1

Answer:

Hydrogen

Lithium Beryllium Fluorine

Sodium Magnesium Chlorine

Potassium Calcium Bromine

Rubidium Strontium Iodine

Explanation:

and much more i had a project about this stuff

Answer 2

Elements on the same period will appear on the same row in the periodic table.

The periodic table is arranged in groups and periods. The vertical columns are the groups while the horizontal rows are the periods. Elements in the same group are chemically similar while elements in the same period have the same number of shells.

The question is incomplete because the letters are not shown. However, elements on the same period will appear on the same row in the periodic table.

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Related Questions

hydrocarbon structures methopane

Answers

what’s the question lol ??

Zuzana tests a common household substance and finds that it has a pH of 3.

What type of substance is in the scenario?

acidic
basic
salt
neutral

Answers

a pH of 3 is acidic! hope this helps:)

a pH of 0-6 is acidic
a pH of 7 is neutral
a pH of 8-14 is basic

pH is a measurement of amount of hydronium ion H₃O⁺ in a given sample. More the value of hydronium ion concentration, more will be the solution acidic. The given substance is acidic. The correct option is option A.

What are acid and base?

Acid is a solution which releases H⁺ hydrogen ion when dissolved in water. Base are the solution which releases hydroxide ion OH⁻ ion when dissolved in water. The pH of acid is between 0-7 on pH scale while for base pH range is from 7-14.

On subtracting pH from 14, we get pOH which measures the concentration of hydroxide ion in a given solution. pH depend on the temperature. At room temperature pH scale is between 0 to 14. pH of neutral solution is 7.

Therefore, the given substance is acidic.  The correct option is option A.

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Describe the process of dimensional analysis and explain why it is so useful in chemical problem solving.

Answers

Answer:

Dimensional Analysis (also called Factor-Label Method or the Unit Factor Method) is a problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value. It is a useful technique.

11.
A sample of TNT, C-H5N306, has 7.30 1021 nitrogen atoms. Determine the numbers of
hydrogen atoms in this sample of TNT.
021​

Answers

Answer:

1.22 × 10^22 H atoms

Explanation:

From this question, TNT has the chemical formula: C-H5N306. The number of nitrogen atoms in the TNT substance is said to be 7.30 × 10^21 atoms.

The number of hydrogen atoms in the same TNT substance can be got using mole ratio. Based on the chemical formula, the mole ratio of hydrogen to nitrogen is 5:3 i.e. H5N3.

This means that;

Number of atoms of hydrogen = 5/3 of the number of atoms of nitrogen.

Hence, number of H atoms = 5/3 × 7.30 × 10^21

number of H atoms = (7.30 × 5/3) × 10^21

number of H atoms = (36.5/3) × 10^21

number of H atoms = 12.1666 × 10^21

number of H atoms = 1.2166 × 10^22 atoms.

Approximately, number of H atoms in TNT is 1.22 × 10^22 atoms.

Which of the following best defines an allotrope?
Question 1 options:


Crystalline forms


Carbon atoms


Different forms of the same element


Similar bonding arrangements between atoms

Answers

Answer:

hi buddy!! here is ur ans: carbon atoms

Question 5
2 pts
To determine the density of an irregularly shaped object, a student immersed the object in 32.2 mL of water in a graduated cylinder, causing the level of the water to rise to 37.8 ml. If the object had a mass of 12.4 g, what is the density of the object?

O 0.32 g/mL
O 1.4 g/mL
O 3.4 g/mL
O 2.2 g/mL

Help quick right answer gets brainliest !!

Answers

Answer:

Explanation:

2.2 g/mL is the answer.

17 Which changes decrease the rate of reaction between magnesium and air?
1.heating the magnesium to a higher temperature
2.using a higher proportion of oxygen in the air
3.using magnesium ribbon instead of powdered magnesium
A 1, 2 and 3
B 1 only
C 2 only
D 3 only​

Answers

Im pretty sure the answer is d

Using magnesium ribbon instead of powdered magnesium decrease the rate of reaction between magnesium and air.

What is rate of reaction?

Rate of reaction tells about the duration of the completion of the reaction.

Rate of any reaction is directly proportional to the concentration and surface area of the reactant, temperature, catalyst, no. of collision, activation energy, etc.

So, if we magnesium in the ribbon instead of powdered magnesium the surface area of the reactant side decreases which results in the decrease of the rate of reaction.

Hence, option (D) is correct i.e. rate of reaction decreases on using magnesium ribbon instead of powdered magnesium.

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Example of market structures of monopoly

Answers

Answer: A monopoly is the absence of competition in the market.

Explanation:

In such circumstances, the market creates a monopoly of one producer who takes huge capital and dictates prices. An example of a monopoly on the market is the existence of only one company that makes up the entire economic branch. In such circumstances, the monopolist can increase the product's price without losing the entire sale, i.e., operating successfully. In that situation, the monopolist remains the only one on the market, and the competition has no access to the market.

Describe the liquid state of matter and give an example besides water.​

Answers

Liquids. A liquid has a definite volume but takes the shape of its container. Examples of liquids include water and oil. Gases may liquefy when they cool, as is the case with water vapor.

The formula for calculating power is work divided by time (power = work + time). What are two ways of stating the same relationship?
work = power + time
nwork s power x time
power
time = work x power
Opower workx time
time
Work

Answers

Answer:

See the answer below

Explanation:

The formula for calculating power is such that;

  power = work/time

Two ways to restate the relationship between the 3 variables would be to make time and work the subject of the formula respectively.

1. When time if made the subject of the formula;

 time = work/time

2. When work is made the subject of the formula;

work = power x time

100
80
100 mL
water vapor
Which statement describes what will happen if a student
pushes the plunger
to compress the water vapor?
A. The total number of water particles will increase.
B. The amount of energy in the water particles will decrease.
C. The amount of empty space between the water particles will
decrease.
O D. The total volume of the water particles will increase.


I will mark brainliest

Answers

Answer: c (the amount of empty space between the water particles will decrease)

Explanation: i got it right:)

1. a metal with 3 valence electrons, used in cans.
2. a period 3 element that will not react naturally.
3. has 5 valence electrons and in period 3.
4. the most reactive metal.

Answers

Answer:

.

Explanation:

1. aluminum

2. argon

3. phosphorus

4. francium

I cant really explain this one

PLEASE HELP I WILL MARK BRAINIEST ITS TIMED

Answers

Answer:

I assume air pollution.

Explanation:

If you incinerate something, usually fire or some kind of heating element is used. A byproduct of fire and/or burning is smoke, which can pollute the air.

Answer:

A. Air pollution

Explanation:

In the incineration Factories they produce items And Air pollution

if an atom has 15 protons and a mass of 31 how many neutrons will it have

Answers

Answer:

16 neutrons

Explanation:

now that protons are equal to electrons, there are 15 electrons. The mass is equal to 31.0, which is the ≡ of protons and ≡ neutrons added together. To find the number of neutrons, subtract the atomic # from the total mass #. 31-15=16 this would be equal to 16 now that the atomic has 31 and the mass is 15 subtract them ... you would get 16 neutrons inside the nucleus.

hope this helped ((((: if it did then please mark brainliest and have a wonderful day d:

Answer:

16

Explanation:

To find the neutrons, it's always mass-atomic number. Since the atomic number for an atom is always the protons, it's really mass-protons.

31-15=16

I just wanted to say you guys on this app are no help. I have asked 4 question sin the past 1-2 hours and not one has been answered. If you know a lot about Chemistry please help me.​

Answers

What’s the question?

If atomic size is the distance from the nucleus to the valence electrons, does the size of the atom get bigger or smaller as you go from period 1 to 3? Explain?

Answers

Smaller the atomic size get smaller as it goes across a period. This is because periods all have the same amount of valence electron shell numbers (like period 2 has 2 valance shells around the atom) but at the same exact time, the number of protons increase going down the period. This means there’s more/a stronger pull from the protons to the outer balance electrons making the valance electron layers pull inward more, but on the next layer of new balance electron shell is formed so the distance between the outer most balanced electron in the protons is wider than the previous level, but like before the gap decreases as a you go down the period. Hope this makes sense

please one more last help me on my task to go on baby corp​

Answers

Answer:?

Explanation: i'm confused with this and i know i should be writing this in comments but if you can explain me the question maybe i could help you

When [H+] = 4.0 × 10–9 M in water at 25°C, then
Kw =1.0×10–14.
b. pOH = 7.
c. [H3O+] = [OH–].
d. pH= 7
e. A-D are all correct

Answers

Answer:

a. Kw = 1.0 × 10⁻¹⁴

Explanation:

a. Let's consider the self-ionization of water.

2 H₂O(l) ⇄ H₃O⁺(aq) + OH⁻

The ion-product of water (Kw) at 25 °C is:

Kw = [H₃O⁺][OH⁻] = 1.0 × 10⁻¹⁴

c. Considering [H⁺] = [H₃O⁺] = 4.0 × 10⁻⁹ M, the concentration of OH⁻ is:

[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 2.5 × 10⁻⁶ M

b. We can calculate the pOH using the following expression.

pOH = -log [OH⁻] = -log 2.5 × 10⁻⁶ = 5.6

d. We can calculate the pH using the following expression.

pH = -log [H⁺] = -log 4.0 × 10⁻⁹ = 8.4

When [H+] = 4.0 × 10–9 M in water at 25°C, then the [tex]Kw =1.0\times 10^-^1^4.[/tex]

What is dissociation constant?

Kw is the dissociation constant or ionization constant of water.

The self-ionization of water will be

[tex]\rm 2 H_2O(l) = H_3O^+(aq) + OH^-[/tex]

The dissociation constant of the water at 25°C will be

[tex]\rm Kw = [H_3O^+][OH^-] = 1.0 \times 10^-^1^4[/tex]

Thus, the correct option is a. [tex]Kw =1.0\times 10^-^1^4.[/tex]

Learn more about dissociation constant

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What do the rows in the Periodic Table tell us?

Answers

Answer:

The rows tell you how many shells there are of the atom.

A chemical reaction in a lab experiment actually produces 1.23mol of BeBr2. The theoretical yield is 220g. To two decimal places, what is the percentage yield

Answers

Answer:

Percent yield = 94.62%

Explanation:

Given data:

Actual yield of BeBr₂ = 1.23 mol

Theoretical yield of BeBr₂ = 220 g

Percent yield = ?

Solution:

Theoretical yield in moles:

Number of moles = mass/molar mass

Number of moles = 220 g/168.82 g/mol

Number of moles = 1.30 mol

Percent yield:

Percent tiled = actual yield / theoretical yield × 100

by putting values,

Percent yield = 1.23 mol / 1.30 mol × 100

Percent yield = 0.9462 × 100

Percent yield = 94.62%

Which energy source releases the most carbon dioxide?
O solar
O wind
O nuclear
O coal

Answers

Answer:

Coal

Explanation:

Coal is by far the worst emitter, followed by natural gas, with solar, wind and nuclear all low-carbon.

Coal, a non-renewable energy source releases the most carbon dioxide into the atmosphere.

What are energy sources?

Energy sources refers to the various sources in which energy for man's needs are obtained.

There are two types of energy sources:

Renewable energy sourcesNon-renewable energy sources

The non-renewable energy sources such as coal release large amounts of carbon dioxide until The atmosphere.

Therefore, Coal, a non-renewable energy source releases the most carbon dioxide into the atmosphere.

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How many moles of sulfate ions are in 756.91 mg of iron (III) sulfate?

Answers

Answer:

1 Answer. 1 mole of ferric sulfate contains 2 moles of iron, and 12 moles of oxygen atoms, and three moles of sulfate ions.Sep 29, 2016

Explanation:

A complex absorbs photons with an energy of 4.10×10^−19 J. What is the wavelength of these photons? If this is the only place in the visible spectrum where the complex absorbs light, what color would you expect the complex to be?

Answers

Answer:

483 nm corresponds to blue light hence the complex will appear orange.

Explanation:

Using the formula;

E= hc/λ

Where;

E = energy of the photon

h = Plank's constant (6.6*10^-34Js)

c = Speed of light (3*10^8 ms-1)

λ = wavelength

λ = hc/E

λ = 6.6*10^-34 * 3*10^8/4.10×10^−19

λ = 4.83 * 10^-7 or 483 nm

483 nm corresponds to blue light

Using the colour wheel approach, if a complex absorbs blue light, then it will appear orange.

is pure water a solution

Answers

Answer: No because a solution is a homogeneous MIXTURE of two or more substances. Water is a pure substance. It is made of hydrogen and oxygen, but shares none of their properties. So it’s pure.

Explanation:

Select the correct answer.
Which of the following might cause chemical contamination when used near food?
A.
furniture polish
B.
steel can
Ос.
glass container
OD. plastic bag
Reset
Next

Answers

Sounds like it would be Furniture Polish because it’s Polish and it tends to have strong chemicals.

How many atoms of each element are in the chemical formula NH4NO2?
1 nitrogen, 1 hydrogen, and 3 oxygen
O 1 nitrogen, 4 hydrogen, and 3 oxygen
2 nitrogen, 4 hydrogen, and 3 oxygen
O 5 nitrogen, 1 hydrogen, and 1 oxygen

Answers

5 nitrogen, 1 hydrogen, and 1 oxygen I think

Rust has the same properties as iron


True

False

Answers

Answer:

false

Explanation:

Match the definition with the correct term: 1/12th the mass of a carbon-12 atom.

Answers

Answer:

hydrogen atom but see the note below.

Explanation:

This is either the most common hydrogen ion or a hydrogen atom. It cannot be either of hydrogen's isotopes.

One of the waste byproducts of a nuclear reactor using uranium-235 is strontium-90 with half-life of about 28 years. If we have 100 pounds of this radioactive waste:

Answers

Answer:

(a) 140 years

(b) 3.125 pounds

Explanation:

QuestIons

(a) How long is five half-life

(b)  How much radioactive strontium is left after five half-life

Given that:

Half-life is about 28 years; &

There are 100 pounds of this radioactive waste

Five half-life will be;

= 28 × 5

= 140 years

The amount of radioactive remaining after five half-life is:

[tex]= 100 \times( \dfrac{1}{2}) ^5[/tex]

= 100 × 0.03125

= 3.125 pounds


How are the cells in our bodies organized? Cells are organized into ______ , _____
, and
_____ systems?
quick answer pls!

Answers

Answer:

Cell --> Tissues --> Organs ---> Organ System ---> Organism

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