Answer:
Electrons arrangement change is almost constant down the group, hence nuclear charge is almost constant.
But the energy levels on which electrons are arranged increase down the group, hence shielding or screening effect increases.
Answer:
True
Explanation:
Competition is the act of competing with one another for a particular resource. An example is two animals quarrelling over a food or two people quarreling over who lost their money. Competing is a type of rivalry in which two people compete for one resource. The answer for this question is True.
Explanation:
there are 6 significant values
Answer:
156 g
Explanation:
Let's consider the following reaction.
2 NaN₃(s) → 2 Na(s) + 3 N₂
(g)
We can find the moles of N₂ using the ideal gas equation.
P × V = n × R × T
1.50 atm × 60.0 L = n × (0.08206 atm.L/mol.K) × 305 K
n = 3.60 mol
The molar ratio of N₂ to NaN₃ is 3:2. The moles of NaN₃ are:
3.60 mol N₂ × (2 mol NaN₃ / 3 mol N₂) = 2.40 mol NaN₃
The molar mass of NaN₃ is 65.01 g/mol. The mass of NaN₃ is:
2.40 mol × 65.01 g/mol = 156 g
In the early 1900's, Paul Drüde came up with the "sea of electrons" metallic bonding theory by modeling metals as a mixture of atomic cores (atomic cores = positive nuclei + inner shell of electrons) and valence electrons. Metallic bonds occur among metal atoms. Whereas ionic bonds join metals to non-metals, metallic bonding joins a bulk of metal atoms. A sheet of aluminum foil and a copper wire are both places where you can see metallic bonding in action.
Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms. Even a soft metal like sodium (melting point 97.8°C) melts at a considerably higher temperature than the element (neon) which precedes it in the Periodic Table. Sodium has the electronic structure 1s22s22p63s1. When sodium atoms come together, the electron in the 3s atomic orbital of one sodium atom shares space with the corresponding electron on a neighboring atom to form a molecular orbital - in much the same sort of way that a covalent bond is formed.
The difference, however, is that each sodium atom is being touched by eight other sodium atoms - and the sharing occurs between the central atom and the 3s orbitals on all of the eight other atoms. Each of these eight is in turn being touched by eight sodium atoms, which in turn are touched by eight atoms - and so on and so on, until you have taken in all the atoms in that lump of sodium. All of the 3s orbitals on all of the atoms overlap to give a vast number of molecular orbitals that extend over the whole piece of metal. There have to be huge numbers of molecular orbitals, of course, because any orbital can only hold two electrons.
The electrons can move freely within these molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalized. The metal is held together by the strong forces of attraction between the positive nuclei and the delocalized electrons Hope this helped
