Question

the unit of mass used for atoms: *
moa - mass of atom
uam - unit of atomic mass
amu - atomic mass unit
g - grams
which of the following statements is true regarding the nucleus: *
most of the mass of the atom is in the nucleus
protons and electrons are in the nucleus
most of the nucleus is empty space with little mass for the atom.
electrons and neutrons are in the nucleus
which of the following is true regarding electrons:
they are found inside the nucleus of the atom
the number of electrons always equals the number of protons
electrons have a positive charge
the mass of an electron is so small that we dont count it

Explanation:

First Question:

• moa - mass of atom: This is not a standard unit.
• uam - unit of atomic mass: Incorrect notation. The correct abbreviation is amu.
• amu - atomic mass unit: This is the standard unit used to measure the mass of atoms.
• g - grams: Grams are too large a unit for measuring atomic mass.

• most of the mass of the atom is in the nucleus: True. Protons and neutrons (in the nucleus) have significant mass compared to electrons (outside the nucleus).
• protons and electrons are in the nucleus: False. Electrons are outside the nucleus.
• most of the nucleus is empty space with little mass for the atom: False. The nucleus is dense and contains most of the atom's mass.
• electrons and neutrons are in the nucleus: False. Electrons are outside the nucleus.

• They are found inside the nucleus of the atom: False. Electrons are outside the nucleus.
• The number of electrons ALWAYS equals the number of protons: True (in a neutral atom).
• Electrons have a positive charge: False. Electrons have a negative charge.
• The mass of an electron is so small that we don't count it: While electrons have small mass, in some calculations (like in chemistry for molar mass of molecules with many atoms) their collective mass is considered, but in basic atomic structure discussions, the main mass contributors are protons and neutrons. However, the most accurate among the options given based on basic atomic structure (assuming a neutral atom context) is "The number of electrons ALWAYS equals the number of protons".

Answer:

amu - atomic mass unit

Second Question: