This element has an atomic number smaller than magnesium and 3 electrons in its valence shell

0:00 一<br> what is 18,000 divided by 450,000 in scientific notation

ankoles [38]

Answer:

4 × 10-2

(scientific notation)

= 4e-2

(scientific e notation)

= 40 × 10-3

(engineering notation)

(thousandth; prefix milli- (m))

Explanation:

All of the anwsers

3 0

3 years ago

Element X has two isotopes. If 72.0% of the element has an isotope mass of 84.9 atomic mass units, and 28.0% of the element has

bija089 [108]

<h2>Answer:</h2>

Average atomic mass of an element is the sum of the masses of its isotopes each multiplied by its natural abundance

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ \sum\limits \: \% age \: of \: each \: isotope \times Atomic \: mass }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 72 \times84.9 + 28 \times 87 }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 6112.8 + 2436 }{100} \\$

$\footnotesize \longrightarrow \: \rm Average \: atomic \: mass = \dfrac{ 8548.8 }{100} \\$

$\footnotesize \longrightarrow \: \bf Average \: atomic \: mass = 85.488 \: amu \\$

8 0

2 years ago

In your home, you can turn off your television set but all of your other appliances will stay on. This is because the appliances

Leto [7]

Answer:

in parallel

Explanation:

4 0

3 years ago

A chemist dissolves 248mg of pure hydrochloric acid in enough water to make up 140mL of solution.Calculate the pH of the solutio

evablogger [386]

Answer : The pH of the solution is, 1.31

Explanation : Given,

Mass of $HCl$ = 248 mg = 0.248 g (1 mg = 0.001 g)

Volume of solution = 140 mL

Molar mass of $HCl$ = 36.5 g/mole

First we have to calculate the concentration of hydrochloric acid.

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Mass of }HCl\times 1000}{\text{Molar mass of }HCl\times \text{Volume of solution (in mL)}}$

Now put all the given values in this formula, we get:

$\text{Molarity}=\frac{0.248g\times 1000}{36.5g/mole\times 140mL}=0.0485mole/L=0.0485M$

The concentration of HCl is, 0.0485 M

As we know that, HCl dissociates to give hydrogen ion and chloride ion.

The dissociation reaction is:

$HCl\rightarrow H^++Cl^-$

Concentration of HCl = Concentration of H⁺ = Concentration of Cl⁻ = 0.0485 M

Now we have to calculate the pH of the solution.

pH : It is defined as the negative logarithm of hydrogen ion concentration.

Mathematically,

$pH=-\log [H^+]$

$pH=-\log (0.0485)$

$pH=1.31$

Therefore, the pH of the solution is, 1.31

6 0

3 years ago

Look at the screenshot ;)

SashulF [63]

This is not the best way to organize a periodic table because two elements might have similar atomic mass.

<h3>What is periodic table?</h3>

Periodic table is a chart in which arrangement of chemical elements are done.

In the early periodic table elements are arranged on the basis of their atomic masses, while after sometime Moseley arranged the periodic table on the basis of atomic number as he proposed that properties of an element is justified on the basis of number if electrons.

And mass of two substances may be same so it is difficult to differentiate between them.

Hence, two elements might have similar atomic mass.

To know more about periodic table, visit the below link:

brainly.com/question/14514242

#SPJ1

6 0

2 years ago