Ionic bonding does not involve the sharing of electrons, that one is false. In ionic bonding, the metal's electrons are given to the non-metal, so that they're both like the nearest noble gas (full electron shells.) They are then drawn together because one has a negative charge (the non-metal) and one has a positive charge (the metal.)
Oxide ions have a 2+ charge: This is false, oxide ions have a 2- charge.
Electrons do have a negative charge, this is true.
Hydrogen molecule: pretty sure this is true. We know this because both atoms are non-metals.
The last one is true: a covalent bond is a shared pair of electrons between two atoms, however be aware that there can be more than one covalent bond between two molecules.
Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²
