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3 years ago

J. Explain how an atom's valence electron configuration determines its place on the periodic table.

Chemistry

1 answer:

Darya [45]3 years ago

5 0

Answer:

Elements having same valence electrons are placed in <u>same group.</u>

Explanation:

First, let's start with some basic concepts of modern periodic table:

1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers

The Modern periodic table is divided into Periods and groups .

Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.

Same period have same number of atomic orbital(Shell)

Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.

So, elements showing same valency are placed in same group.

All alkali are place in group 1 and have 1 valance electron in the outermost shell

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The nucleus of a comet is made up of rock, dust, and frozen gasses
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3 years ago

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Using this balanced equation: 2 NaOH + H2SO4 —> H2O + Na2SO4

mars1129 [50]

<h3>Answer:</h3>

266.325 g

<h3>Explanation:</h3>

We are given the balanced equation;

2NaOH + H₂SO₄ → H₂O + Na₂SO₄

Mass of NaOH as 150 g

We are required to determine the mass of Na₂SO₄ that will be formed.

<h3>Step 1: Determine the number of moles of NaOH</h3>

Moles = Mass ÷ molar mass

Molar mass of NaOH is 40.0 g/mol

Therefore;

Moles of NaOH = 150 g ÷ 40 g/mol

= 3.75 moles

<h3>Step 2: Determine the number of moles of sodium sulfate formed</h3>

From the equation 2 moles of NaOH reacts with sulfuric acid to form 1 mole of sodium sulfate.
Therefore; mole ratio of NaOH : Na₂SO₄ is 2 : 1

Thus, moles of Na₂SO₄ = Moles of NaOH ÷ 2

= 3.75 moles ÷ 2

= 1.875 moles

<h3>Step 3: Determine the mass of Na₂SO₄ produced.</h3>

we know that;

Mass = Moles × Molar mass

Molar mass of Na₂SO₄ is 142.04 g/mol

Therefore;

Mass of Na₂SO₄ = 1.875 moles × 142.04 g/mol

= 266.325 g

Thus, the mass of sodium sulfate formed 266.325 g

7 0

3 years ago

Propane burns in oxygen to produce carbon dioxide and water what is the percent yeild

amid [387]

Answer:

The percentage yield is 78.2g

Explanation:

Given, mass of propane = 42.8 g , sufficient O2 percent yield = 61.0 % yield.

Reaction - C3H8(g)+5O2(g)------> 3CO2(g)+4H2O(g)

First we need to calculate the moles of propane

Moles of propane = $\frac{42.8}{44.096}$ g.mol-1

= 0.971 moles

So, moles of CO2 from the moles of propane

1 mole of C3H8(g) = 3 moles of CO2(g)

So, 0.971 moles of C3H8(g) = ?

= 2.913 moles of CO2

So theoretical yield = 2.913 moles $\times$ 44.0 g/mol

= 128.2 g

So, the actual mass of CO2 = percent yield $\times$ theoretical yield / 100 %

= 61.0 % $\times$ 128.2 g / 100 %

= 78.2 g

the mass of CO2 that can be produced if the reaction of 42.8 g of propane and sufficient oxygen has a 61.0 % yield is 78.2 g

4 0

3 years ago

An oxide of nitrogen is 25.9% N by mass, has a molar mass of 108 g/mol, and contains no nitrogen-nitrogen or oxygen-oxygen bonds

Sonja [21]

Answer:

The compound is N2O4

Explanation:

We have certain important pieces of information about the compound;

1) it is an oxide (a binary compound of nitrogen and oxygen)

2) there are no N-N bonds present

3) there are no O-O bonds present

Since it contains only nitrogen and oxygen then nitrogen accounts for 25.9% of the molecule by mass then oxygen should account for (100-25.9) = 74.1% oxygen

Relative atomic mass of oxygen = 16

Relative atomic mass of nitrogen = 14

We now deduce the empirical formula

Nitrogen. Oxygen

25.9/14. 74.1/16

1.85/1.85. 4.6/1.85 (divide through by the lowest ratio)

1 2

Empirical formula is NO2

To find the molecular formula

(NO2)n = 108

(14+2(16))n= 108

46n=108

n= 108/46

n= 2

Therefore molecular formula= N2O4

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3 years ago

The bond in which bonded atoms share electrons is called a(n)

Rashid [163]

Answer:

covalent bond

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2 years ago

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J. Explain how an atom's valence electron configuration determines its place on the periodic table.​

J. Explain how an atom's valence electron configuration determines its place on the periodic table.