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3 years ago

which of the following elements is in the same as period as phosphorous? a. magnesium b. nitrogen c. carbon d. oxygen

Chemistry

2 answers:

nirvana33 [79]3 years ago

4 0

A) Magnesium
Period is the horizontal row in the periodic table.

wariber [46]3 years ago

4 0

A.) Element Phosphorous belongs to group 15 and period 3, magnesium belongs to group 2 and period 3. Hence magnesium is the correct answer. Hope this helps!

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Which of the following is true of the electrons in the Bohr model of an atom?

NARA [144]

Answer:

They exist at specific energy levels

Explanation:

6 0

3 years ago

18.A 2.50 L sample of dry air in a cylinder exerts a pressure of

Vlada [557]

Answer:

$\boxed{\text{7.50 L}}$

Explanation:

The temperature and amount of gas are constant, so we can use Boyle’s Law.

$p_{1}V_{1} = p_{2}V_{2}$

Data:

$\begin{array}{rclrcl}p_{1}& =& \text{3.00 atm}\qquad & V_{1} &= & \text{2.50 L} \\p_{2}& =& \text{1.00 atm}\qquad & V_{2} &= & ?\\\end{array}$

Calculations:

$\begin{array}{rcl}3.00 \times 2.50 & =& 1.00V_{2}\\7.500 & = & 1.00V_{2}\\V_{2} & = &\textbf{7.50 L}\\\end{array}\\\text{The volume of the gas is } \boxed{\textbf{7.50 L}}$

4 0

3 years ago

How do you know measurements are accurate

IRINA_888 [86]

Answer:

Accuracy refers to the closeness of a measured value to a standard or known value. For example, if in lab you obtain a weight measurement of 3.2 kg for a given substance, but the actual or known weight is 10 kg, then your measurement is not accurate. In this case, your measurement is not close to the known value.

Explanation:

6 0

3 years ago

A sample of a compound contains 3.21 g of sulfur and 11.4 g of fluorine. Which of the following represents the empirical formula

Murrr4er [49]

Answer: The empirical formula will be $SF_6$

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of S= 3.21 g

Mass of F = 11.4 g

Step 1 : convert given masses into moles.

Moles of S = $\frac{\text{ given mass of S}}{\text{ molar mass of S}}= \frac{3.21g}{32g/mole}=0.1moles$

Moles of F = $\frac{\text{ given mass of F}{\text{ molar mass of F}}= \frac{11.04g}{19g/mole}=0.6moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For S= $\frac{0.1}{0.1}=1$

For F = $\frac{0.6}{0.1}=6$

The ratio of S: F= 1: 6

Hence the empirical formula is $SF_6$

7 0

3 years ago

The isotope of an unknown element, X, has a mass number of 79. The most stable ion of this isotope has 36 electrons and has a 22

Tema [17]

Answer:

A) False

B) True

C) True

D) True

Explanation:

A) False. If the charge of the atom is +2 means that you have two protons more than number of electrons. If you have 36 electrons you must have <em>38 protons.</em> Also, the electrons are not in the nucleus.

B) True. The isotope of X contains 38 protons, two more than the electron number.

C) True. The mass number is the number of protons + number of neutrons.

If the mass number is 79 and there are 38 protons you must have 41 neutrons.

D) True. You can now the identity of the atom with the number of protons that is the same than atomic number. The strontium, Sr, is the atom with 38 as atomic number.

I hope it helps!

3 0

3 years ago