Check its reactivity the most reactive is the most metallic. And remember in third group of the periodic table contains all metals
Si -Atomic number -14 -1s2 2s2 2p6 3s2 3p2 - 4 valence electrons
Answer:
Carbonates (CO3-2), phosphates (PO4-3) and sulfides (S-2) are insoluble.
The exceptions are the alkali metals and the ammonium ion.
The correct question is: How many moles are in 
atoms of boron.
Answer: There are 145 moles present in atoms of boron.
Explanation:
According to the mole concept, there are 
atoms present in one mole of every substance.
Hence, number of moles present in atoms is calculated as follows.
Thus, we can conclude that there are 145 moles present in atoms of boron.
Answer:
The answer is: <u>Al2O3</u>
Explanation:
The data they give us is:
To find the empirical formula without knowing the grams of the compound, we find it per mole:
- 0.545 g Al * 1 mol Al / 27 g Al = 0.02 mol Al
- 0.485 g O * 1 mol O / 16 g O = 0.03 mol O
Then we must divide the results obtained by the lowest result, which in this case is 0.02:
- 0.02 mol Al / 0.02 = 1 Al
- 0.03 mol O / 0.02 = 1.5 O
Since both numbers have to give an integer, multiply by 2 until both remain integers:
Now the answer is given correctly:
