Biology Quiz 1 CH???

Subatomic particles in the nucleus of an atom (with their correct charges)

Protons (positive charge), neutrons (neutral)

The element Ca, calcium, has an atomic number of 20. How many electrons are present in its valence shell?

2 electrons

Subatomic particles that orbit the atomic nucleus

Electrons

Elements needed for life

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS)

Atomic number of an atom is

the number of protons in its nucleus

When do salts form

They form when negative anions bind to positive cations to create ionic compounds

Why is Oxygen highly reactive

Because it has high electronegativity and it bonds to other elements to form strong chemical bonds

Isotopes have varying numbers of…

Neutrons in the nucleus, which result in a different atomic mass of the same element

Hydrogen bonds form between…

neighboring water molecules

Salts and sugars dissolve in water therefore they are …

hydrophilic

Non-polar covalent bonds form when…

two atoms share electrons evenly

When a base is added to a solution what does it do to the hydrogen ion concentration of the solution

It decreases

pH of acids

less than pH 7

pH of bases

greater than pH 7

As water cools down, it forms

more hydrogen bonds between neighboring water molecules

Water is neutral, therefore water has…

an equal balance of hydrogen (H+) ions and hydroxide (OH-) ions

What do buffers do to the pH level of a solution

stabilizes the pH levels