Answer:
See explanation
Explanation:
The question is incomplete because the images of the models are absent. However, i will try to give you a general description of what the correct answer should be.
Beryllium is a member of group 2 in the periodic table. Beryllium has an atomic number of 4. This implies that it has four protons in its nucleus and four electrons in its shells. In a neutral atom, the number of electrons on the shells is equal to the number of protons in the nucleus.
The electronic configuration of Beryllium is 1s2 2s2. This implies that it should have two shells each containing only two electrons each.
Since we are using white foam balls for protons and black foam balls for neutrons, the clear plastic will contain four white foam balls and five black foam balls since the mass number of beryllium is 9 and number of neutrons = mass number - number of protons.
Four blue foam balls hanging from strings will represent the electrons around the nucleus.
Any model that corresponds to the description above is the correct answer.
Answer:
D
Explanation:
Mendeleev periodic table predicted the properties of undiscovered element like the eka-aluminium.
Answer:
<h2>0.73 g/cm³</h2>
Explanation:
The density of a substance can be found by using the formula
From the question we have
We have the final answer as
<h3>0.73 g/cm³</h3>
Hope this helps you
Answer:
H₂ is excess reactant and O₂ the limiting reactant
Explanation:
Based on the chemical reaction:
2H₂(g) + O₂(g) → 2H₂O
<em>2 moles of H₂ react per mole of O₂</em>
<em />
To find limiting reactant we need to convert the mass of each reactant to moles:
<em>Moles H₂ -Molar mass: 2.016g/mol-:</em>
10g H₂ * (1mol / 2.016g) = 4.96 moles
<em>Moles O₂ -Molar mass: 32g/mol-:</em>
22g O₂ * (1mol / 32g) = 0.69 moles
For a complete reaction of 0.69 moles of O₂ are needed:
0.69mol O₂ * (2mol H₂ / 1mol O₂) = 1.38 moles of H₂
As there are 4.96 moles,
<h3>H₂ is excess reactant and O₂ the limiting reactant</h3>
