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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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How many particles are present in0.24moles of carbon?
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Answer:

1.45 x 10²³ particles

Explanation:

Given parameters:

Number of moles of carbon  = 0.24moles

Unknown:

Number of particles = ?

Solution:

A mole of a substance contains the Avogadro's number of particles.

 The Avogadro's number of particles is 6.02 x 10²³

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  0.24 moles of carbon will contain 0.24 x 6.02 x 10²³  = 1.45 x 10²³ particles

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Consider the following reaction mechanism:
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Answer:

  • <em><u>Step 2 (the slow step).</u></em>

Explanation:

The rate-determining step is always the slow step of a mechanism.

That is so, because it is the slow step which limits the reaction.

Imaging that for assembling a toy you have process of three steps:

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  • 2. glue the pieces and hold the toy until the glue hardens, which takes 1 hour: meaning finishingh 1 toy in 1 hour.

  • 3. pack the toy, which takes 2 minutes: meaning that you can pack 60/2 = 30 toys in one hour.

The time to glue and hold one toy until the glue hardens determines that you can assemble 1 toy in 1 hour and not 60 toys or 30 toys.

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The highest point on the graph of the wave is called the crest and the lowest point is called the trough.The line through the center of the wave is the resting position of the medium if there was no wave passing through.

The different properties of a wave include:

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The wavelength of a wave is the distance between two two crests of a wave or two troughs of a wave. The wavelength is usually represented in physics by the Greek letter lambda (λ).  

The frequency of a wave is the number of  times per second that the wave cycles. Frequency is measured in Hertz or cycles per second and often represented by the lower case "f."  

The period of the wave is the time between wave crests. The period is measured in time units such as seconds and is usually represented by the upper case "T".  

The period and frequency are closely related to each other. The period equals  1 over the frequency and the frequency is equal to one over the period. They are reciprocals of each other as shown in the following formulas.

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