Answer:
D
Explanation:
If the atom is neutral, the sum of the core and valence electrons is the same as the number of protons, which is the atomic number of the element. So if the sum of the core and valence electrons in a neutral atom equals 25 , that is the number of protons in the atomic nucleus, and the atomic number of the element.
Reorder 4Fe and 3O2.
3O2 + 4Fe
Answer:
you can identify an unknown substance by measuring its density and comparing your results to a list of known densities. Density=mass/volume. Assume that you have to identify an unknown metal. You can determine the mass of the metal on a scale.
Answer:
0.295 g Co
General Formulas and Concepts:
<u>Chemistry - Atomic Structure</u>
- Reading a Periodic Table
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Explanation:
<u>Step 1: Define</u>
3.01 × 10²¹ atoms Co
<u>Step 2: Identify Conversions</u>
Avogadro's Number
Molar Mass of Co - 58.93 g/mol
<u>Step 3: Convert</u>
<u />
= 0.294552 g Co
<u>Step 4: Check</u>
<em>We are given 3 sig figs. Follow sig fig rules and round.</em>
0.294552 g Co ≈ 0.295 g Co
No, because you are not changing the chemical make-up of the paper