Answer:
Both <u>elements </u>and <u>compounds</u> can be classifies as pure substances because they have distinct properties and composition.
Explanation:
Elements and compounds are considered as pure substances because both are always formed form are have same kind of atoms.
For example,
Carbon dioxide is compound. It always consist of one carbon atom and two oxygen atoms.
Water is compound it always have same kind of atoms two hydrogen and one oxygen that's why compounds are considered as pure substances.
Same is the case with elements. For example,
Hydrogen is element and it always consist of H atoms.
Iron is another element and it always have iron atoms.
So elements and compounds are always consist of same substances that's why they are considered as pure.
Answer:
See explanation
Explanation:
The central atom in the perbromate ion is bromine. The chemical symbol of bromine is Br. There are no lone pairs around the central bromine atom. The ion is tetrahedral in shape hence we expect a bond angle of 109°. 27 which is the ideal tetrahedral bond angle. The actual bond angle of the prebromate ion is 109.5°. The perbromate ion is BrO4^-
The observed bond angle is very close to the ideal value because of the absence of lone pairs of electrons from the central atom in the ion.
B. 11,540
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
General formulas used in decay:

T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
Nt=25 g
No=100 g
t1/2=5770 years

(If this is correct, can I have Brainlist?)
Answer:
D) anomalous volcanoes such as those in Hawaii