Answer:
answer is b
Explanation:
All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor
B the app and then it was just a was the last time you got it to a friend or we
A compound is a pure substance formed by the chemical combination of two or more different elements.
A compound may be splitted into simpler substances by chemical reactions, and has different properties to those of the elements that form it.
The composition of a compound is fixed: every piece of a compound has the same kind of atoms, bonded in the same way and proportion.
Some examples of compounds are H₂O, NaCl, H₂O₂, CH₃COOH. As you see, they have a chemical formula which states the kind and number of the atoms that form them.
They are different to mixtures, which are formed by two or more compounds, in a variable proportion, and can be separated by physical media. Some examples of mixtures are the solutions (e.g. NaCl dissolved in H₂O), and some solid mixtures (e.g. a mixture of marbles and sand).
I would think that the answer would be three
Because of the prefix tri- in "tigonal"
Tri- means 3, as in tricycle or triangle
So, it would make sense for the answer to be 3
