Group 1A (the alkali metals) almost always form cations (positive ions). They'd need anions (negative ions) to ionic bond with. Beryllium (Be) is group 1A already and forms Be+ cation. Bromine is a halogen, and forms Br-, an anion. Platinum is a metal, and usually won't ionic bond with anything. Francium is rare and highly radioactive, plus it so happens to be group 1A as well. Only bromine can form the anion that the group 1A cations need.
Answer:
being polar, it can easily dissolve other polar substances or substances with ionic bonds like nacl
Answer:
A
Explanation:
To answer this, we need to use Gay-Lussac's law, which states that:
, where P is pressure and T is temperature
The initial pressure we're given is 4.5 atm (so P1 = 4.5) and the temperature is 45.0°C; however, we need to change Celsius to Kelvins, so add 273 to 45.0: 45.0 + 273 = 318 K (so T1 = 318).
The final pressure is what we want to find, but we do know the final temperature is 3.1°C. Converting this to Kelvins, we get: 3.1 + 273 = 276.1 K, which means T2 = 276.1.
Plug these values in:

Multiply both sides by 276.1:
≈ 3.9 atm
The answer is thus A.
Explanation:
1. Democritus proposes the existence of atoms
2. Dalton's atomic theory
3. J. J. Thomson discovers the electron
4. Rutherford's gold foil experiment
5. Bohr model
6. Schrödinger's Wave Mechanics model of the atom
The first idea about matter containing atoms dates back to Greek philosophers. One of them was Democritus .
In 1808 Dalton put forward his atomic theory
In 1897 J.J Thomson discovered cathode rays using his gas discharge tube experiment.
In 1911, Ernest Rutherford proposed the nuclear model of the atom using experiments on the gold foil.
Neils Bohr in 1913 suggested his own atomic model
Erwin Schrodinger formulated the wave equation of electrons
Learn more;
Dalton atomic theory brainly.com/question/1979129
Rutherford gold foil experiment brainly.com/question/1859083
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