Answer:
Both are unreactive.
Explanation:
Atom Number of Electrons
A 2
D 10
The two atoms A and D are very stable and unreactive.
Valence electrons the outermost shell electrons in a neutral atom.
The number of valence electrons in A is 2
The number of valence electrons in D is 8
The atoms are stable and unreactive because for A, its two electrons are in the k-shell in which the maximum number of electrons here is 2. It has a noble configuration which makes it stable.
For atom D, the outermost electrons are in the L-shell in which the maximum number of electrons is 8. This also makes it stable and unreactive.
Both atoms will be reluctant to lose or gain electrons.
Group two elements are
a. Metals b. Nonmetals c. Transition metals is c
<h3>
Answer:</h3>
150 g Si
<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Atomic Structure</u>
- Reading a Periodic Table
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[Given] 3.2 × 10²⁴ atoms Si
[Solve] grams Si
<u>Step 2: Identify Conversions</u>
Avogadro's Number
[PT] Molar Mass of Si - 28.09 g/mol
<u>Step 3: Convert</u>
- [DA] Set up:

- [DA] Multiply/Divide [Cancel out units]:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. Instructed to round to 2 sig figs.</em>
149.266 g Si ≈ 150 g Si
Answer: 
Explanation:

where,
= boiling point of solution = ?
= boiling point of solvent (X) = 
= freezing point constant = 
m = molality
i = Van't Hoff factor = 1 (for non-electrolyte like urea)
= mass of solute (urea) = 29.82 g
= mass of solvent (X) = 500.0 g
= molar mass of solute (urea) = 60 g/mol
Now put all the given values in the above formula, we get:


Therefore, the freezing point of solution is 