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3 years ago

If an atom has three shell and number of valence electrons are two. Is this element metal

Chemistry

1 answer:

cluponka [151]3 years ago

3 0

Answer:

Metal

Element: Calcium

Valency: 2

Explanation:

To find the element, let's use the periodic table. (Look below)

We already went past 3 shells, just need the 2 electrons after it.

Just skip to the 4th row and count 2 to the right

We end up at Calcium.

Calcium is a metal and we're also on the alkaline earth metals column.

Calcium will need to lose 2 electrons to reach stability, so the valency is 2.

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2 years ago

Read 2 more answers

A 20.00-mL sample of a weak base is titrated with 0.0568 M HCl. At the endpoint, it is found that 17.88 mL of titrant was used.

nata0808 [166]

Answer: 0.0508mL

Explanation: Using the basic formula that states: C acid * V acid = C base * V base. we have:0.568 * 17.88 = 20 * C base.

therefore concentration of the base is 1.0156/20 = 0.0508 mL

7 0

3 years ago

What is the best textile fiber?

boyakko [2]

Answer:

Cotton is the world's most widely used natural fibre and still the undisputed "king" of the global textiles industry.

Explanation:

7 0

3 years ago

A. Consider the following neutral electron configurations in which n has a constant value. Which configuration would belong to t

NeTakaya

Answer:

2s2 2p5

Rb < Sr< Sn< Te<I

Explanation:

Electron affinity is the ability of an atom to accept electrons to form negative ions.

Electron affinity is a periodic trend that decreases down the group but increases across the period.

This accounts for the trends observed in the answer. The atom having the electronic configuration, 2s2 2p5 must be a halogen and it exhibits the highest value of electron affinity.

Also, since electron affinity increases across the period, the electron affinities of the elements increases. Therefore, the arrangement of atoms as shown in the answer depends on increasing electron affinity.

6 0

3 years ago

Measurements show that unknown compound has the following composition: element mass 38.7 % calcium, 19.9 % phosphorus and 41.2 %

Mademuasel [1]

Answer:

D) empirical formula is: C₃P₂O₈

Explanation:

Given:

Mass % Calcium (Ca) = 38.7%

Mass % Phosphorus (P) = 19.9%

Mass % oxygen (O) = 41.2 %

This implies that for a 100 g sample of the unknown compound:

Mass Ca = 38.7 g

Mass P = 19.9 g

Mass O = 41.2 g

Step 1: Calculate the moles of Ca, P, O

Atomic mass Ca = 40.08 g/mol

Atomic mass P = 30.97 g/mol

Atomic mass O = 16.00 g/mol

$Moles\ Ca = \frac{38.7g}{40.08g/mol} =0.966\ mol\\\\Moles\ P = \frac{19.9g}{30.97g/mol} =0.643\ mol\\\\Moles\ O = \frac{41.2g}{16.00g/mol} =2.58\ mol$

Step 2: Calculate the molar ratio

$C = \frac{0.966}{0.643} =1.50\\\\P = \frac{0.643}{0.643} = 1.00\\\\O = \frac{2.58}{0.643} =4.00$

Step 3: Calculate the closest whole number ratio

C: P: O = 1.50 : 1.00 : 4.00

C : P : O = 3:2:8

Therefore, the empirical formula is: C₃P₂O₈

7 0

3 years ago