2. Atoms & Elements

Which of the following describes how a neutral atom forms a positive ion (cation)?

Which ion has the same electron configuration as an atom of He?

Which of the following best describes a hydrogen ion?

In a neutral compound formed from Al^{3+} ions and S^{2-} ions, what is the ratio of Al^{3+} ions to S^{2-} ions?

When hydrogen atoms in a water molecule experience an unequal pull of electrons due to the electronegativity of oxygen, what is the resulting partial charge on each hydrogen atom?

In a water molecule, the oxygen atom has a ______ charge and the hydrogen atoms have a ______ charge.

What is the charge of a potassium ion (K^+)?

Which of the following best describes a hydronium ion?

In order to have a positive charge, an atom must have ________.

Which ions are formed when Sr(CH3COO)2 dissociates in water?

Which is a characteristic of all ions?

When writing the formula for an ionic compound, why must the total positive and negative charges balance?

What is the most common charge on a cobalt ion in the compound CoCl2?

When an atom of magnesium (Mg) loses two electrons, which ion is formed?

A positive ion forms when an atom ______.