Question

use the provided image and the phrases below to correctly complete the sentences. labels may be used more than once or not at all.
potassium
k
19
39.098
potassium is a __________
an atom of the most common isotope of potassium has a nucleus composed of 19 ________ and ______ ________
the nucleus of a neutral potassium atom is surrounded by __________
(labels above: protons, trace element, 21, electrons, 20, nonessential element, 19, 49, bulk element, neutrons, 29)

Explanation:

First Sentence: "Potassium is a ______"

Potassium (K) is a metal, so from the labels (like "metal element"), it fits. It's also a bulk element in biological contexts and reactive, but "metal element" is accurate chemically.

Second Sentence: "An atom of the most common isotope of potassium has a nucleus composed of 19 ____ and __ ____"

Atomic number (19) = protons. Mass number of common K isotope is 39 (19 + 20). So nucleus has 19 protons and 20 neutrons (neutrons = mass number - atomic number = 39 - 19 = 20).

Third Sentence: "The nucleus of a neutral potassium atom is surrounded by ______"

Neutral atom has equal protons and electrons. Protons = 19, so electrons = 19, surrounding the nucleus.

Answer:

bulk element (or reactive element, or metal element - based on typical potassium properties; from the labels, "bulk element" or "reactive element" or "metal element" are options. Let's use "metal element" as potassium is a metal)