Answer:
38
Explanation:
Symbol: Sr
Atomic mass: 87.62 u
Electrons per shell: 2,8,18,8,2
Atomic number: 38
Electron configuration: [Kr] 5s2
Van der Waals radius: 255 pm
Valence electrons: two
Answer:
Sofia the firstttdbshsgshaksus
Answer: AZ is the insoluble choice.
Explanation:
Z is an anion of a weak electronegative element. Hence, it bounds lightly with the highly electropositive cation A to form AZ.
AZ is not as ionic as AX, AY, BX, BY and BZ, so it is insoluble in water and yields precipitate on reaction with the salt of a weaker metal.
Following are the chemical elements that have atomic mass greater than 173.5 u and atomic number less than 75.
1. Lutetium
Atomic Number = 71
Atomic Mass = 174.97 u
2. Hafnium
Atomic Number = 72
Atomic Mass = 178.49 u
3. Tantalum
Atomic Number = 73
Atomic Mass = 180.95 u
4. Tungsten
Atomic Number = 74
Atomic Mass = 183.85 u
