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Stella [2.4K]
3 years ago
10

Use the portion of the periodic table shown below to answer the questions.

Chemistry
2 answers:
Basile [38]3 years ago
8 0
Part 1: Potassium, and Rubidium.
Part 2: Calcium has 20 protons and 20 electrons because the atomic number for calcium is 20 and that determines how many protons there are and in an atom, the number of protons is the same number of electrons. Calcium has about 20 neutrons. I got the number of Neutrons by subtracting the mass number(40.078) and the atomic number(20), I got 20.078. Round to the nearest whole number because you cannot have half or partial neutron. So, Calcium has 20 protons, 20 electrons, and 20 neutrons,

Hope this helps and please mark as brainliest!
lbvjy [14]3 years ago
4 0

<u>Answer:</u>

For 1: The two elements having same properties as sodium are potassium and rubidium.

For 2: Calcium has 20 protons, 20 electrons and 20 neutrons.

<u>Explanation:</u>

  • <u>For 1:</u>

The elements which belong to the same group, tend to have same properties. Group represents the vertical row in the periodic table. Hence, the elements which have same properties as sodium are potassium and rubidium.

  • <u>For 2:</u>

Atomic number is defined as the number of protons or electrons in an element.

Atomic number = Number of electrons = Number of protons

Atomic mass is defined as the sum of number of protons and neutrons in an element.

Atomic mass = Number of protons + Number of neutrons

Atomic number of calcium is 20. So, number of protons and electrons will be 20.

Atomic mass of calcium is 40.

40 = Number of neutrons + 20

Number of neutrons = 20

Hence, calcium has 20 protons, 20 electrons and 20 neutrons.

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The density of a sample of metal is calculated using these three different sets of data: 1.2 g/mL, 1.4 g/mL, and 1.1 g/mL. If th
Iteru [2.4K]
Accurate data means the data experimentally obtained are close to the true value. Precise data means the data obtained are close to one another. In this case, the data are close to the true value which is 1.2 and the data are relatively close to one another. Hence the set is both accurate and precise.
8 0
3 years ago
How many molecules of carbon dioxide are in 9.080 x 10 ^-1 mol?
kakasveta [241]

Answer:

5.46 8 x 10²³ molecules.

Explanation:

  • <em>Knowing that every one mole of a substance contains Avogadro's no. of molecules (NA = 6.022 x 10²³).</em>

<em><u>Using cross multiplication:</u></em>

1.0 mole → 6.022 x 10²³ molecules.

9.08 x 10⁻¹ mole → ??? molecules.

∴ The no. of molecules of CO₂ are in 9.08 x 10⁻¹ mol = (6.022 x 10²³ molecules) ( 9.08 x 10⁻¹ mole) / (1.0 mol) = 5.46 8 x 10²³ molecules.

6 0
3 years ago
Consider the following equilibrium: 2SO^2(g) + O2(9) = 2 SO3^(g)
saul85 [17]

Answer:

At equilibrium, the forward and backward reaction rates are equal.

The forward reaction rate would decrease if \rm O_2 is removed from the mixture. The reason is that collisions between \rm SO_2 molecules and \rm O_2\! molecules would become less frequent.

The reaction would not be at equilibrium for a while after \rm O_2 was taken out of the mixture.

Explanation:

<h3>Equilibrium</h3>

Neither the forward reaction nor the backward reaction would stop when this reversible reaction is at an equilibrium. Rather, the rate of these two reactions would become equal.

Whenever the forward reaction adds one mole of \rm SO_3\, (g) to the system, the backward reaction would have broken down the same amount of \rm SO_3\, (g)\!. So is the case for \rm SO_2\, (g) and \rm O_2\, (g).

Therefore, the concentration of each species would stay the same. There would be no macroscopic change to the mixture when it is at an an equilibrium.

<h3>Collision Theory</h3>

In the collision theory, an elementary reaction between two reactants particles takes place whenever two reactant particles collide with the correct orientation and a sufficient amount of energy.

Assume that \rm SO_2\, (g) and \rm O_2\, (g) molecules are the two particles that collide in the forward reaction. Because the collision has to be sufficiently energetic to yield \rm SO_3\, (g), only a fraction of the reactions will be fruitful.

Assume that \rm O_2\, (g) molecules were taken out while keeping the temperature of the mixture stays unchanged. The likelihood that a collision would be fruitful should stay mostly the same.

Because fewer \!\rm O_2\, (g) molecules would be present in the mixture, there would be fewer collisions (fruitful or not) between \rm SO_2\, (g) and \rm O_2\, (g)\! molecules in unit time. Even if the percentage of fruitful collisions stays the same, there would fewer fruitful collisions in unit time. It would thus appear that the forward reaction has become slower.

<h3>Equilibrium after Change</h3>

The backward reaction rate is likely going to stay the same right after \rm O_2\, (g) was taken out of the mixture without changing the temperature or pressure.

The forward and backward reaction rates used to be the same. However, right after the change, the forward reaction would become slower while the backward reaction would proceed at the same rate. Thus, the forward reaction would become slower than the backward reaction in response to the change.

Therefore, this reaction would not be at equilibrium immediately after the change.

As more and more \rm SO_3\, (g) gets converted to \rm SO_2\, (g) and \rm O_2\, (g), the backward reaction would slow down while the forward reaction would pick up speed. The mixture would once again achieve equilibrium when the two reaction rates become equal again.

5 0
3 years ago
The electronegativity values of fluorine, oxygen, and hydrogen are compared in the table. Comparison of Electronegativity Elemen
Dvinal [7]

The hydrogen bonding in H₂O is stronger than that of HF

Explanation:

Hydrogen bonds are special dipole-dipole attraction in which electrostatic attraction is established between hydrogen atom of one molecule and the electronegative atom of a neighboring molecule.

  • The strength of hydrogen bonds depends on the how electronegative an atom is.
  • Electronegativity refers to the tendency of an atom to gain electrons.
  • The higher the value, the higher the tendency.
  • This why oxygen with a higher electronegativity will form a stronger hydrogen bond with hydrogen compared to fluorine.

Learn more:

hydrogen bond brainly.com/question/12408823

#learnwithBrainly

4 0
3 years ago
9. According to an "alternative theory", H2O is
Jlenok [28]

Answer:(4) ----accepts  a proton

Explanation:

H2O water can produce both hydrogen and   hydroxide ions

H2O --> H+ + OH-

According to the Bronsted-Lowry theory, it can be a proton donor and a proton acceptor.this means that It can donate a hydrogen ion to become its conjugate base, or  can accept a hydrogen ion to form its conjugate acid,

When , a water molecule, H2O accepts a proton it will act as a Brønsted-Lowry base especially when dissolved in a strong acidic medium. for eg

HCl + H2O(l) → H3O+(aq) + Cl−(aq)

Here, Hydrochloric acid is a strong acid and ionizes completely in  water, since it is more acidic than water, the water will act as a base.

6 0
3 years ago
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