Question

atoms consist of a positively charged center called a(n) ____________.*
o proton
o neutron
o electron
o nucleus

the negative charged particles outside the nucleus of an atom are ____________.*
o extracellular material
o electrons
o neutrons
o quarks

Explanation:

1. An atom's positively - charged center is the nucleus. Protons are positively charged particles within the nucleus, but the center as a whole is called the nucleus. Neutrons are neutral and electrons are negatively charged.
2. The negatively - charged particles outside the nucleus of an atom are electrons. Extracellular material is related to cells, not atoms. Neutrons are neutral and quarks are sub - particles that make up protons and neutrons.

Answer:

1. D. nucleus
2. B. electrons