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2 years ago

True or false: An element has two layers of electrons. The electrons in the outermost layer are called distance electrons.

Chemistry

2 answers:

valentinak56 [21]2 years ago

3 0

Answer:

true

Explanation:

masya89 [10]2 years ago

3 0

The answer is True, do you need to know the reason behind why it’s true?

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How many atoms are in 0.31 moles

padilas [110]

1 mole contains = 6.02x10^23 atoms. 0.31mole contains = 0.31x6.02x10^23 = 1.8662x10^23.

4 0

2 years ago

PLS help

viktelen [127]

Answer:

d . Sc2O5

Explanation:

Hello,

In this case, when forming oxides from a metal and oxygen, for us to find out each element's subscript, we must exchange them as shown below, considering +5 for scandium:

$Sc^{+5}_2O^{-2}_5$

For that reason, the answer is d . Sc2O5

Best regards.

3 0

3 years ago

Read 2 more answers

Determine the mass in grams of 3.75 x 10^21 atoms of zinc. (the mass of one mole of zinc is 65.39 g)

Nastasia [14]

Answer: The mass in $3.75 \times 10^{21}$ atoms of zinc is 0.405 g.

Explanation:

Given: Atoms of zinc = $3.75 \times 10^{21}$

It is known that 1 mole of every substance contains $6.022 \times 10^{23}$ atoms. So, the number of moles in given number of atoms is as follows.

$Moles = \frac{3.75 \times 10^{21}}{6.022 \times 10^{23}}\\= 0.622 \times 10^{-2}\\= 0.0062 mol$

As moles is the mass of a substance divided by its molar mass. So, mass of zinc (molar mass = 65.39 g/mol) is calculated as follows.

$Moles = \frac{mass}{molar mass}\\0.0062 mol = \frac{mass}{65.39 g}\\mass = 0.405 g$

Thus, we can conclude that the mass in $3.75 \times 10^{21}$ atoms of zinc is 0.405 g.

6 0

2 years ago

Which element has properties most similar to Bromine? <br> A) F <br> B) Kr <br> C) S <br> D) Se

Stells [14]

Fluorine (F) will have properties similar to Bromine (Br) because it belongs to the same group as Bromine.

7 0

3 years ago

Read 2 more answers

Write the formula for potassium oxide. why do you not need prefixes in the name

Molodets [167]

Potassium oxide: K₂O.

There's no need for prefixes since K₂O is an ionic compound.

<h3>Explanation</h3>

Find the two elements on a periodic table:

Potassium- K- on the left end of period four.
Oxygen- O- near the right end of periodic two.

Elements on the bottom-left corner of the periodic table are metals. Those on the top-right corner are nonmetals.

Potassium is a metal,
Oxygen is a nonmetal.

A metal and a nonmetal combine to form an ionic compound. Potassium oxide is likely to be an ionic compound. It contains two types of ions:

Potassium ions: Potassium is group 1 of the periodic table. It is an alkaline metal. Like other alkaline metals such as sodium Na, potassium K tends to lose one electron and form ions of charge +1 in compounds. The ion would be K⁺.

Oxide ions from oxygen: Oxygen is the second most electronegative element on the periodic table. It tends to gain two electrons and form the oxide ion $\text{O}^{2-}$ when it combines with metals.

The two types of ions carry opposite charges. They shall pair up at a certain ratio such that they balance the charge on each other. The charge on each $\text{O}^{2-}$ ion is twice that on a $\text{K}^{+}$ ion. Each $\text{K}^{+}$ would pair up with two $\text{O}^{2-}$ . Hence the subscript in the formula: $\text{K}_{\bf 2}\text{O}$ .

There are two classes of compounds:

Covalent compounds, which need prefixes, and
Ionic compounds, which need no prefix.

Prefixes are needed only in covalent compounds. For instance in the covalent compound carbon dioxide $\text{CO}_2$ , the prefix di- indicates that there are two oxygen atoms in the formula $\text{CO}_2$ . However, there's no need for prefix in ionic compounds such as $\text{K}_2\text{O}$ .

7 0

3 years ago