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3 years ago

How many outer electrons does cesium and magnesium have?

1 answer:

6 0

The outer electrons of an element are called the valence electrons. They help make an element stable.

Cesium : 1 valence electron.

Magnesium : 2 valence electrons

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The most familiar elements are typically the most

rodikova [14]

-Are the most used in daily life and basic human needs

(such as oxygen,nitrogen,carbon, etc)

4 0

3 years ago

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What is 6.3cm =____mm please help me

azamat

63 mm multiply the length value by 10 bb ♡

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3 years ago

A chemist must prepare of sodium hydroxide solution with a pH of at . He will do this in three steps: Fill a volumetric flask ab

77julia77 [94]

Answer:

0.0400 g for the example given below.

Explanation:

pH value is not provided, so we'll solve this problem in a general case and then we will use an example to justify it.

By definition, $pH = -log[H_3O^+]$ .
NaOH is a strong base, as it's a hydroxide formed with a group 1A metal, so it dissociates fully in water by the equation: $NaOH (aq)\rightarrow Na^+ (aq) + OH^- (aq)$ .
From the equation above, using stoichiometry we can tell that the molarity of hydroxide is equal to the molarity of NaOH: $[NaOH] = [OH^-]$ .
Concentration of hydroxide is then equal to the ratio of moles of NaOH and the volume of the given solution. Moles themselves are equal to mass over molar mass, so we obtain: $[OH^-] = [NaOH] = \frac{n_{NaOH}}{V} = \frac{m_{NaOH}}{M_{NaOH}V}$ .
We also know that $pOH = 14.00 - pH = -log[NaOH]$ . Take the antilog of both sides: $10^{-pOH} = 10^{pH - 14.00} = [NaOH] = \frac{m_{NaOH}}{M_{NaOH}V}$ .
Solve for the mass of NaOH: $m_{NaOH} = 10^{pH - 14.00}\cdot M_{NaOH}\cdot V$ .

Now, let's say that pH is given as 12.00 and we use a 100-ml volumetric flask. Then we would obtain:

$m_{NaOH} = 10^{12.00 - 14.00}\cdot 39.997 g/mol\cdot 0.100 L = 0.0400 g$

7 0

3 years ago

Someone answer this please...

boyakko [2]

Answer:

120 mol Mg

General Formulas and Concepts:

Chemistry - Stoichiometry

Using Dimensional Analysis

Explanation:

Step 1: Define

120 moles H₂

Step 2: Identify Conversions

RxN: 3 mol H₂ = 3 mol Mg

Step 3: Stoichiometry

$120 \ mol \ H_2(\frac{3 \ mol \ Mg}{3 \ mol \ H_2} )$ = 120 mol Mg

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3 years ago

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Elements donate 2 electron to produce a cation with a 2+ charge

hammer [34]

Answer: alkaline earth metals (group-IIA)

Explanation:

The element which donates the electron is known as electropositive element and forms a positively charged ion called as cation. The element which accepts the electrons is known as electronegative element and forms a negatively charged ion called as anion.

Alkaline earth metals donate 2 valence electrons to acquire noble gas configuration.

For example: Berrylium is the first alkaline earth metal with atomic number of 4 and thus has 4 electrons

Electronic configuration of berrylium:

$[Be]:4:1s^22s^2$

Berrylium atom will loose two electrons to gain noble gas configuration and form berrylium cation with +2 charge.

$[Be^{2+}]:2:1s^2$

Thus Elements donate 2 electron to produce a cation with a 2+ charge are alkaline earth metals.

5 0

3 years ago