Mass of metal piece is 611 g and volume of graduated cylinder is 25.1 mL. When metal piece is placed in the graduated cylinder water level increases to 56.7 mL. The increase in volume is due to volume of metal piece that gets added to the volume of water.
Thus, volume of metal piece can be calculated by subtracting initial volume from the final one.
Thus, volume of metal piece will be 31.6 mL. The mass of metal piece is given 611 g, density of metal can be calculated as follows:
Therefore, density of metal is 19.33 g/mL.
Answer:
The elements become less reactive.
Explanation:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction and reactivity increases because of greater electron affinity.
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased. The electron affinity decreases because of shielding effect and thus atom become less reactive.
Periodic table is arranged according to atomic size and other properties.
The last one is the answer to your question. D is the answer
1) Molecular formula of ammonium sulfide
(NH4)2 S
2) That means that there are 2*4 = 8 atoms of hydrogen in each molecule of ammoium sulfide, so in 5.20 mol of molecules will be 8 * 5.20 mol = 41.6 moles of atoms of hydrogen
3) To pass to number of atoms multiply by Avogadro's number: 6.022 * 10^23
41.6 moles * 6.022 * 10^23 atoms / mol = 250.5 * 10^23 = 2.50 * 10^25 atoms
Answer: 2.50 * 10^25
