Answer:
Calcium can be ignited and will when burning react with both oxygen and nitrogen forming calcium oxide, CaO, and calcium nitride, Ca3N2.
The correct answer is b. an element
The explanation:
when the ELEMENT is define as substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means. Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen
Ex: diamond will be broken into carbon as well.
and SUBSTANCE: Material composed of only one kind of matter throughout (same atoms or same molecules).
Answer:
C
Explanation:
Calcium is an element with a total of 20 electrons.
It has 4 shells with a configuration of:
2, 8, 8, 2
Option C is the most similar to calcium but the number of shells is not complete.
It still requires two more shells with 8 and two electrons respectively.
Taking into account the definition of density, the density of the metal is 16.33 
.
<h3>Definition of density</h3>
Density is a quantity that allows us to measure the amount of mass in a certain volume of a substance. Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:
From this expression it can be deduced that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.
<h3>Density of the metal in this case</h3>
In this case, you know that:
- Mass= 34.3 g
- Volume= 2.1 mL
Replacing in the definition of density:
Solving:
<u><em>density= 16.33 </em></u>
In summary, the density of the metal is 16.33 .
Learn more about density:
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