All the radioactive elements are found in the last group of the Periodic Table.

True
False

Answer: physically

Explanation: it's a physical change because the air that fills it up does not affect its chemical compound like I'd you mix metal in salt water

Answer:Vinegar

Explanation:

In the image shown above, there are 3 elements (option C).

Element is one of the simplest chemical substances that cannot be decomposed in a chemical reaction or by any chemical means and made up of atoms all having the same number of protons.

As stated above, all elements are made up of backbone structures called atoms. The atoms of an element are the same.

According to this question, an image is given showing atoms of different colors. Each atom with the same color belongs to a single element.

Since there are there colors, this means that there are three elements in the picture.

Learn more about elements at: https://brainly.com/question/13794764

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Answer:

36 electrons

Explanation:

The # of protons is always equal to the atomic number. In the case of Sr (Strontium), it is 38 protons.

The 2+ at the end means that it has a charge of +2, meaning that it LOST two electrons to become a cation with a full valence shell. So, 38 - 2 = 36 electrons

Answer:

38 protons 36 electrons 30 neutron because of 29 isotope

Answer:

5.44 moles of nitrogen required.

Explanation:

Given data:

Number of moles of NH₃ = 10.88 mol

Moles of N₂ required = ?

Solution:

Chemical equation:

N₂ +  3H₂         →       2NH₃

Now we will compare the moles nitrogen and hydrogen.

               NH₃          :           N₂

                 2             :           1

               10.88        :         1/2×10.88 = 5.44mol

5.44 moles of nitrogen required.

Answer:

By bonding due to the attractive forces

Answer:

I hope this helps!Good luck

Answer:

This description can be expressed as follows:

Y > W > XY>W>X

And,

W=ZW=Z

From these expressions we are able to find out that the saltiest cell description is Y, while the less salty is X.

Now, salt is well known as a dehydrating agent. In a process called osmosis cells placed in a salty liquid environment lose water, how?

Well, cells have a semipermeable membrane, in which some substances can get inside. Cells also have water inside. If a cell is placed in a quite salty liquid environment, salt will make the water inside the cells to come out, drying the cell and diminishing its size.

So, in this case, according to the expressions above, Cell Y will look the smallest, while cell X will look the biggest.

If we pour pure water in each liquid, the salt concentration will change and each cell will begin to grow bigger, but the saltiest cell will still be smaller than the others with less salt concentration.

Answer:

Explanation:

So chemical changes require a change on a molecular level that cannot be reversed because they form some new substance. Souring milk is not something you can reverse, and the process of it souring produces new molecules.

Answer: The empirical formula is [tex]H_4P_2O_7[/tex]

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of H= 2.270 g

Mass of P = 34.80 g

Mass of O = 62.93 g

Step 1 : convert given masses into moles

Moles of H =  [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{2.270g}{1g/mol}=2.270[/tex]

Moles of P =  [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{34.80g}{31g/mol}=1.122[/tex]

Moles of O = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{62.93g}{16g/mol}=3.933[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For H =  [tex]\frac{2.270}{1.122}=2[/tex]

For P=    [tex]\frac{1.122}{1.122}=1[/tex]

For O =   [tex]\frac{3.933}{1.122}=3.5[/tex]

The simples ratio will be = H: P : O= 4: 2: 7

Hence the empirical formula is [tex]H_4P_2O_7[/tex]

Answer:

Increase

Explanation:

Hope it helps you

Answer:

Decrease

Explanation:

If the oil you're referring to is just some normal oil, it'll lessen the friction and cause it to side more smoothly

Answer:

4.99*10²³ molecules of N₂O₄ are in 76.3 g of N₂O₄

Explanation:

Avogadro's Number is the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number represents a quantity without an associated physical dimension. Avogadro's number applies to any substance.

You know that the molar mass of N₂O₄ is 92.02 g/mol, and you have 76.3 g. Then you can apply the following rule of three: 92.02 grams are present in 1 mole of the compound, 76.3 grams in how many moles are they?

[tex]amount of moles= \frac{76.3 grams*1 mole}{92.02 grams}[/tex]

amount of moles= 0.83 moles

Then, you can apply another rule of three: if by definition of Avogadro's number 1 mole of the compound has 6.023*10²³ molecules, 0.83 moles of the compound, how many molecules will it have?

[tex]amount of molecules= \frac{0.83 moles*6.023*10^{23}molecules }{1 mole}[/tex]

amount of molecules= 4.99*10²³

4.99*10²³ molecules of N₂O₄ are in 76.3 g of N₂O₄

Answer:

each planet has a different force of gravity

Explanation:

Weight = mass× gravity

As gravity changes from place to place and also from planet to planet so weight changes.

Answer:

Option B. Plutonium-243

Explanation:

To know the the correct answer to the question, we shall write the balanced equation for the reaction showing curium-247 (²⁴⁷Cm) emitting alpha particle. This is illustrated below:

²⁴⁷₉₆Cm —> ᵐₙX + ⁴₂He

Next, we shall determine m, n and X. This can be obtained as follow:

247 = m + 4

Collect like terms

247 – 4 = m

243 = m

Thus, m is 243

96 = n + 2

Collect like terms

96 – 2 = n

94 = n

Thus, n is 94

m = 243

n = 94

ᵐₙX => ²⁴³₉₄X => ²⁴³₉₄Pu

Thus, the equation is:

²⁴⁷₉₆Cm —> ²⁴³₉₄Pu + ⁴₂He

From the illustrations above, the daughter nuclei formed is Plutonium-243 (²⁴³₉₄Pu)

Answer:

Plutonium-243

Explanation:

Answer: Temperature

Explanation:

Answer: Temperature

Explanation: can i get brainliest plss

1. s = 2 m/s

2. d = 130 m

3. t = 7 s

4. d = 56 mi

5.  t = 0.15625 h

6. s = 72 mph

Given

The speed,distance,and time

Required

Units that have not been converted / calculated

Solution

For motion at a constant speed, the formula can be used:

d = v x t or d = s x t

v = velocity

s = speed

1. s = d : t = 40 m : 20 s⇒ s = 2 m/s

2. d = s x t = 13 m/s x 10 s ⇒ d = 130 m

3. t = d : s = 63 m : 9 m/s ⇒ t = 7 s

4.  d = s x t = 28 mph x 2 h ⇒ d = 56 mi

5. t = d : s = 24 mi :  153.6 mph ⇒ t = 0.15625 h

6. s = d : t =1296 mi : 18 h⇒ s = 72 mph

Answer:

option B

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Answer:

Because the compound has a formula of M2O, the number of valence electrons of M should be 1. Therefore, (1) Group 1 is the correct answer because elements in group 1 have 1 valence electron.

Explanation:

Answer: The empirical formula of X  is [tex]Cr_2O_3[/tex]

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of Cr = 68.4 g

Mass of O = 31.5 g

Step 1 : convert given masses into moles.

Moles of Cr =[tex]\frac{\text{ given mass of Cr}}{\text{ molar mass of Cr}}= \frac{68.4g}{52g/mole}=1.31moles[/tex]

Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{31.5g}{16g/mole}=1.97moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Cr = [tex]\frac{1.31}{1.31}=1[/tex]

For O = [tex]\frac{1.97}{1.31}=1.5[/tex]

The simple whole number ratio of Cr : O= 2: 3

Hence the empirical formula is [tex]Cr_2O_3[/tex]

Answer:

Any element in group 1 has just one valence electron. Examples include hydrogen (H), lithium (Li), and sodium (Na). Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons).

Explanation:

How many valence electrons does each element have?

The Group 1 atoms have 1 valence electron. The Group 2 atoms have 2 valence electrons. The Group 3 atoms have 3 valence electrons. The Group 4 atoms have 4 valence electrons.

I hope it's helpful

2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Given

Standard cell notation:

Mg(s) | Mg2+ (aq) || Ag+(aq)| Ag(s)

Required

a balanced redox reaction

Solution

At the cathode the reduction reaction occurs, the anode oxidation reaction occurs

In reaction:  

Ag⁺ + Mg → Ag + Mg²⁺  

half-reactions

Ag⁺ (aq) + e⁻ ---> Ag (s)  x2

2Ag⁺ (aq) + 2e⁻ ---> 2Ag (s)

Mg (s) → Mg²⁺ (aq) + 2e−

a balanced cell reaction

2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Answer:2Ag⁺(aq) + Mg(s)→ 2Ag(s) + Mg²⁺ (aq)

Explanation:

just took test

Answer:

1413.386

Explanation:

Answer:

[tex]6K _{(s)} + N _{2(g)} = = > \:2K _{3} N _{(s)} [/tex]

Potassium nitride

Answer:

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Answer: $6,600[tex]\alpha \sqrt[n]{x} \lim_{n \to \infty} a_n[/tex]

Explanation:

Answer:

Electronegativity is probably the biggest thing that plays into reactivity. Therefore, since fluorine has a higher electronegativity than chlorine, fluorine is more reactive.

Explanation:

I got it right

Answer:

In gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.

Explanation:

Answer:

powder

Explanation:

Between the powder and marble chips, the powder will have a larger surface area.

For the same masses of a solid substance in different forms such as lump, granules or powder, the smaller particle size of each form the larger the surface area.

Surface area increases from lumps to granules and them powder