You are looking for an element in the fourth period and a transition metal. As most have about 3 valence electrons. Gallium and Scandium work perfectly.
Dont know the first one but
2.particles
3. waves/energy
4.radio/air
5.eardrumbs
6.faster/particles
7.slower/
I believe the correct answers from the choices listed above are the second and the last option. At constant pressure, the systems 2A(g) + B(g) ---> 4C(g) and 2C(g) A(s) + B(s) ---> C(g) produces work to the surroundings. <span>When a gas is evolved during a chemical reaction, the gas can be imagined as displacing the atmosphere - pushing it back against the atmospheric pressure. The work done is therefore V*P where V is the volume of gas evolved, and P is the atmospheric pressure. </span>
