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3 years ago

Of the following metals, which is the LEAST reactive? A. K B. Ca C. Na D. Mg

Chemistry

2 answers:

emmainna [20.7K]3 years ago

6 0

The Answer Should Be D.Mg

sladkih [1.3K]3 years ago

3 0

Answer: D. Mg

Explanation:

Chemical reactivity is defined as the tendency of an element to loose of gain electrons.

Metals are the elements which lose electrons and hence, their chemical reactivity will be the tendency to lose electrons.

Their chemical reactivity increases as we move top to bottom in a group because the valence shell come gets far away from the nucleus. Thus, the loss of electron from the valence shell becomes easier due to lesser attraction between nucleus and valence electron.

Their chemical reactivity decreases as we move from left to right in a period .As, the electrons get added up in the same shell, the electron in the outermost orbital gets near to the nucleus. And hence, the electron will be difficult to lose.Thus, the chemical reactivity of metals decreases.

For the given options:

Potassium(K) belongs to Group 1 and period 4 of the periodic table.

Calcium (Ca) belongs to Group 2 and period 4 of the periodic table.

Sodium (Na)belongs to Group 1 and Period 3 of the periodic table.

Magnesium (Mg) belongs to Group 2 and Period 3 of the periodic table.

Order of reactivity of metals follow:

$K>Ca>Na>Mg$

Thus the LEAST reactive metal is Magnesium.

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Explain why the ionization energy to remove a second electron from potassium is higher than the ionization energy to remove four

never [62]

Explanation:

It is more difficult to remove electrons from the second shell or energy level because of the imbalance between the positive nuclear charge and the remaining electrons.

The amount of energy required to remove electrons in ground state of an atom is the ionization energy.
The first ionization energy is the energy needed to remove the most loosely bound electron of an atom in the gas phase in ground state.
The second energy has a greater nuclear pull as it is closer to the nucleus.
Both potassium and silicon have the same number of energy levels.

6 0

3 years ago

Be sure to answer all parts. what are the concentrations of hso4−, so42−, and h in a 0. 31 m khso4 solution? (hint: h2so4 is a s

disa [49]

At equilibrium the concentrations of:

[HSO₄⁻] = 0.10 M;

[SO₄²⁻] = 0.037 M;

[H⁺] = 0.037 M;

There is initially very little H+ and no SO₄²⁻ in the solution. A salt is KHSO₄⁻. All KHSO₄⁻ will split apart into K⁺ and HSO₄⁻ ions. [HSO₄⁻] will initially be present at a concentration of 0.14 M.

HSO₄⁻ will not gain H⁺ to produce H₂SO₄ since H₂SO₄ is a strong acid. HSO₄⁻ may act as an acid and lose H⁺ to form SO₄²⁻. Let the final H⁺ concentration be x M. Construct a RICE table for the dissociation of HSO₄²⁻.

R $HSO_4^-$ ⇄ $H^+ + SO_4^2^-$

I $0.14$

C $- x$ $+x$ $+x$

E $0.14-x$ $x$ $x$

$K_a = 1.3$ × $10^-^2$ for $HSO^-_4$ . As a result,

$\frac{[H^+]. [SO_4^2^-]}{HSO_4^-} = K_a$

$K_a$ is large. It is no longer valid to approximate that $[HSO^-_4]$ at equilibrium is the same as its initial value.

$\frac{x^2}{0.14-y} = 1.3 * 10^-^2$

$x^2+1.3*10^-^2x - 0.14$ × $1.3$ × $10^-^2= 0$

Solving the quadratic equation for $x , x \geq 0$ since $x$ represents a concentration;

$x=0.0366538$

Then, round the results to 2 significant figure;

$[SO_4^2^-] = x = 0.037 mol. L ^-^1$
$[H^+] = x = 0.037 mol. L ^-^1$
$[HSO_4^-] = 0.14 - x = 0.10 mol. L ^-^1$

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2 years ago

Calculate the grams of so2 gas present at stp in a 5.9 l container.

nata0808 [166]

<u>Answer:</u> The mass of sulfur dioxide gas at STP for given amount is 16.8 g

<u>Explanation:</u>

At STP conditions:

22.4 L of volume is occupied by 1 mole of a gas.

So, 5.9 L of volume will be occupied by = $\frac{1mol}{22.4L}\times 5.9L=0.263mol$

Now, to calculate the mass of a substance, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of sulfur dioxide gas = 0.263 mol

Molar mass of sulfur dioxide gas = 64 g/mol

Putting values in above equation, we get:

$0.263mol=\frac{\text{Mass of sulfur dioxide gas}}{64g/mol}\\\\\text{Mass of sulfur dioxide gas}=(0.263mol\times 64g/mol)=16.8g$

Hence, the mass of sulfur dioxide gas at STP for given amount is 16.8 g

7 0

3 years ago

an atmosphere is considered hazardous if it contains a hazardous gas in excess of 10 percent of the hazardous material's:

svlad2 [7]

Lower flammable limit means the lowest concentration of a material that will propagate a flame.

What is hazardous atmosphere?

It is an atmosphere that may expose employees to risk of death, incapacitation, impairment of ability to self-rescue, injury, or acute illness from one or more of following causes

Flammable gas, vapor, or mist in excess of 10 percent of lower flammable limit (LFL)
Airborne combustible dust at concentration that meets or exceeds its LFL

What is lower flammable limit?

It means the lowest concentration of a material that will propagate a flame.
The LFL is usually expressed as percent by volume of material in air (or other oxidant)
Atmospheres with concentration of flammable vapors at or above 10 percent of lower explosive limit (LEL) are considered hazardous when located in confined spaces.
However, atmospheres with flammable vapors below 10 percent of LEL are not necessarily safe. Such atmospheres are too lean to burn

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6 0

1 year ago

As the temperature of water increases its density

fiasKO [112]

Answer:

Explanation:

The warmer the water, the more space it takes up, and the lower its density.

6 0

2 years ago

Read 2 more answers